prac/avl.cpp

#include <functional>

#include "avl.hpp"

#define KNRM  "\x1B[0m"
#define KRED  "\x1B[31m"
#define KGRN  "\x1B[32m"
#define KYEL  "\x1B[33m"
#define KBLU  "\x1B[34m"
#define KMAG  "\x1B[35m"
#define KCYN  "\x1B[36m"
#define KWHT  "\x1B[37m"

static void randomize_node(Node &a) {
    a.key.randomize(8);
    a.pointers.set(0);
    a.value.randomize();
}

void print_green(std::string line) {
    printf("%s%s%s", KGRN, line.c_str(), KNRM);
}

void print_red(std::string line) {
    printf("%s%s%s", KRED, line.c_str(), KNRM);
}

/*
     Pretty-print a reconstructed BST, rooted at node. is_left_child and
     is_right_child indicate whether node is a left or right child of its
     parent.  They cannot both be true, but the root of the tree has both
     of them false.
*/
void AVL::pretty_print(const std::vector<Node> &R, value_t node,
    const std::string &prefix = "", bool is_left_child = false,
    bool is_right_child = false)
{
    if (node == 0) {
        // NULL pointer
        if (is_left_child) {
            printf("%s\xE2\x95\xA7\n", prefix.c_str()); // ╧
        } else if (is_right_child) {
            printf("%s\xE2\x95\xA4\n", prefix.c_str()); // ╤
        } else {
            printf("%s\xE2\x95\xA2\n", prefix.c_str()); // ╢
        }
        return;
    }
    const Node &n = R[node];
    value_t left_ptr = getAVLLeftPtr(n.pointers).xshare;
    value_t right_ptr = getAVLRightPtr(n.pointers).xshare;
    std::string rightprefix(prefix), leftprefix(prefix),
        nodeprefix(prefix);
    if (is_left_child) {
        rightprefix.append("\xE2\x94\x82"); // │
        leftprefix.append(" ");
        nodeprefix.append("\xE2\x94\x94"); // └
    } else if (is_right_child) {
        rightprefix.append(" ");
        leftprefix.append("\xE2\x94\x82"); // │
        nodeprefix.append("\xE2\x94\x8C"); // ┌
    } else {
        rightprefix.append(" ");
        leftprefix.append(" ");
        nodeprefix.append("\xE2\x94\x80"); // ─
    }
    pretty_print(R, right_ptr, rightprefix, false, true);
    printf("%s\xE2\x94\xA4", nodeprefix.c_str()); // ┤
    dumpAVL(n);
    printf("\n");
    pretty_print(R, left_ptr, leftprefix, true, false);
}

void AVL::print_oram(MPCTIO &tio, yield_t &yield) {
    auto A = oram.flat(tio, yield);
    auto R = A.reconstruct();

    for(size_t i=0;i<R.size();++i) {
        printf("\n%04lx ", i);
        R[i].dump();
    }
    printf("\n");
}

void AVL::pretty_print(MPCTIO &tio, yield_t &yield) {
    RegXS peer_root;
    RegXS reconstructed_root = root;
    if (tio.player() == 1) {
        tio.queue_peer(&root, sizeof(root));
        yield();
    } else {
        RegXS peer_root;
        yield();
        tio.recv_peer(&peer_root, sizeof(peer_root));
        reconstructed_root += peer_root;
    }

    auto A = oram.flat(tio, yield);
    auto R = A.reconstruct();
    if(tio.player()==0) {
        pretty_print(R, reconstructed_root.xshare);
    }
}

/*
    Check the AVL invariants of the tree are recursively true:
    (i)   all keys to the left are less than or equal to parent (BST invariant)
    (ii)  all keys to the right are strictly greater than parent (BST invariant)
    (iii) difference in height between sibling subtrees <= 1
    (iv)  the balance bits of each node are correct

    Returns a tuple<bool a, bool b, bool c, address_t height>, where:
    - bool a indicates if BST invariants are true
    - bool b indicates if (iii) is true
    - bool c indicates if (iv) is true
    - height returns the height of the current subtree
*/
std::tuple<bool, bool, bool, address_t> AVL::check_avl(const std::vector<Node> &R,
    value_t node, value_t min_key = 0, value_t max_key = ~0)
{
    if (node == 0) {
        return { true, true, true, 0};
    }
    const Node &n = R[node];
    value_t key = n.key.ashare;
    value_t left_ptr = getAVLLeftPtr(n.pointers).xshare;
    value_t right_ptr = getAVLRightPtr(n.pointers).xshare;
    auto [leftok, leftavlok, leftbbok, leftheight ] = check_avl(R, left_ptr, min_key, key);
    auto [rightok, rightavlok, rightbbok, rightheight ] = check_avl(R, right_ptr, key, max_key);
    address_t height = leftheight;
    if (rightheight > height) {
        height = rightheight;
    }
    height += 1;
    int heightgap = leftheight - rightheight;
    bool leftbal = (getLeftBal(n.pointers)).bshare;
    bool rightbal = (getRightBal(n.pointers)).bshare;
    bool avlok = (abs(heightgap)<2);
    bool bb_ok = false;

    if(heightgap==-1) {
        if(rightbal==1 && leftbal==0){
            bb_ok = true;
        }
    } else if(heightgap==1){
        if(leftbal==1 && rightbal==0){
            bb_ok = true;
        }
    } else if(heightgap==0){
        if(rightbal==0 && leftbal==0) {
            bb_ok = true;
        }
    }
    #ifdef AVL_DEBUG_BB
      if(bb_ok == false){
          printf("BB check failed at node with key = %ld\n", key);
      }
    #endif
    //printf("node = %ld, leftok = %d, rightok = %d\n", node, leftok, rightok);
    return { leftok && rightok && key >= min_key && key <= max_key,
        avlok && leftavlok && rightavlok, bb_ok && leftbbok && rightbbok, height};
}

void AVL::check_avl(MPCTIO &tio, yield_t &yield) {
    auto A = oram.flat(tio, yield);
    auto R = A.reconstruct();

    RegXS rec_root = this->root;
    if (tio.player() == 1) {
        tio.queue_peer(&(this->root), sizeof(this->root));
    } else {
        RegXS peer_root;
        tio.recv_peer(&peer_root, sizeof(peer_root));
        rec_root+= peer_root;
    }
    if (tio.player() == 0) {
      auto [ bst_ok, avl_ok, bb_ok, height ] = check_avl(R, rec_root.xshare);
      printf("BST structure %s\nAVL structure %s\nBalance Bits %s\nTree height = %u\n",
          bst_ok ? "ok" : "NOT OK", avl_ok ? "ok" : "NOT OK", bb_ok? "ok" : "NOT OK", height);
    }
}


/*
  Rotate: (gp = grandparent (if exists), p = parent, c = child)

  This rotates the p -> c link.

   gp                           gp
     \                            \
      p   --- Left rotate  --->    c
       \                          /
        c                        p


   gp                           gp
     \                            \
      p  --- Right rotate  --->    c
     /                              \
    c                                p

*/
void AVL::rotate(MPCTIO &tio, yield_t &yield, RegXS &gp_pointers, RegXS p_ptr,
      RegXS &p_pointers, RegXS c_ptr, RegXS &c_pointers, RegBS dir_gpp,
      RegBS dir_pc, RegBS isReal, RegBS F_gp) {

    bool player0 = tio.player()==0;
    RegXS gp_left = getAVLLeftPtr(gp_pointers);
    RegXS gp_right = getAVLRightPtr(gp_pointers);
    RegXS p_left = getAVLLeftPtr(p_pointers);
    RegXS p_right = getAVLRightPtr(p_pointers);
    RegXS c_left = getAVLLeftPtr(c_pointers);
    RegXS c_right = getAVLRightPtr(c_pointers);
    RegXS ptr_upd;

    // F_gpp: Flag to update gp -> p link, F_pc: Flag to update p -> c link
    // F_pc_l/F_pc_r: indicates whether p -> c link is in the l/r direction
    // F_gpp_l/F_gpp_r: indicates whether gp -> p link is in the l/r direction
    RegBS F_gpp, F_pc_l, F_pc_r, F_gppr, F_gppl;

    // We care about !F_gp. If !F_gp, then we do the gp->p link updates.
    // Otherwise, we do NOT do any updates to gp-> p link;
    // since F_gp==1, implies gp does not exist and parent is root.
    if(player0)
        F_gp^=1;
    mpc_and(tio, yield, F_gpp, F_gp, isReal);

    // i) gp[dir_gpp] <-- c_ptr
    RegBS not_dir_gpp = dir_gpp;
    if(player0)
        not_dir_gpp^=1;
    mpc_select(tio, yield, ptr_upd, F_gpp, p_ptr, c_ptr);

    RegBS not_dir_pc_l = dir_pc, not_dir_pc_r = dir_pc;
    if(player0)
        not_dir_pc_r^=1;
    RegXS c_not_dir_pc; //c[!dir_pc]
    // ndpc_right: if not_dir_pc is right
    // ndpc_left: if not_dir_pc is left
    RegBS F_ndpc_right, F_ndpc_left;
    RegBS nt_dir_pc = dir_pc;
    if(player0)
        nt_dir_pc^=1;

    std::vector<coro_t> coroutines;
    coroutines.emplace_back(
        [&tio, &F_gppr, F_gpp, dir_gpp](yield_t &yield) {
            mpc_and(tio, yield, F_gppr, F_gpp, dir_gpp);
    });
    coroutines.emplace_back(
        [&tio, &F_gppl, F_gpp, not_dir_gpp](yield_t &yield) {
            mpc_and(tio, yield, F_gppl, F_gpp, not_dir_gpp);
    });
    // ii) p[dir_pc] <-- c[!dir_pc] and iii) c[!dir_pc] <-- p_ptr
    coroutines.emplace_back(
        [&tio, &F_ndpc_right, isReal, not_dir_pc_r](yield_t &yield) {
            mpc_and(tio, yield, F_ndpc_right, isReal, not_dir_pc_r);
    });
    coroutines.emplace_back(
        [&tio, &F_ndpc_left, isReal, not_dir_pc_l](yield_t &yield) {
            mpc_and(tio, yield, F_ndpc_left, isReal, not_dir_pc_l);
    });
    coroutines.emplace_back(
        [&tio, &F_pc_l, dir_pc, isReal](yield_t &yield) {
            mpc_and(tio, yield, F_pc_l, dir_pc, isReal);
    });
    coroutines.emplace_back(
        [&tio, &F_pc_r, nt_dir_pc, isReal](yield_t &yield) {
            mpc_and(tio, yield, F_pc_r, nt_dir_pc, isReal);
    });
    run_coroutines(tio, coroutines);

    run_coroutines(tio, [&tio, &gp_right, F_gppr, ptr_upd](yield_t &yield)
        { mpc_select(tio, yield, gp_right, F_gppr, gp_right, ptr_upd);},
        [&tio, &gp_left, F_gppl, ptr_upd](yield_t &yield)
        { mpc_select(tio, yield, gp_left, F_gppl, gp_left, ptr_upd);},
        [&tio, &c_not_dir_pc, F_ndpc_right, c_right](yield_t &yield)
        { mpc_select(tio, yield, c_not_dir_pc, F_ndpc_right, c_not_dir_pc, c_right, AVL_PTR_SIZE);});


     //[&tio, &c_not_dir_pc, F_ndpc_left, c_left](yield_t &yield)
     mpc_select(tio, yield, c_not_dir_pc, F_ndpc_left, c_not_dir_pc, c_left, AVL_PTR_SIZE);


    // ii) p[dir_pc] <-- c[!dir_pc]
    // iii): c[!dir_pc] <-- p_ptr
    run_coroutines(tio, [&tio, &p_left, F_ndpc_right, c_not_dir_pc](yield_t &yield)
        { mpc_select(tio, yield, p_left, F_ndpc_right, p_left, c_not_dir_pc, AVL_PTR_SIZE);},
        [&tio, &p_right, F_ndpc_left, c_not_dir_pc](yield_t &yield)
        { mpc_select(tio, yield, p_right, F_ndpc_left, p_right, c_not_dir_pc, AVL_PTR_SIZE);},
        [&tio, &ptr_upd, isReal, c_not_dir_pc, p_ptr](yield_t &yield)
        { mpc_select(tio, yield, ptr_upd, isReal, c_not_dir_pc, p_ptr, AVL_PTR_SIZE);});

    run_coroutines(tio, [&tio, &c_left, F_pc_l, ptr_upd](yield_t &yield)
        { mpc_select(tio, yield, c_left, F_pc_l, c_left, ptr_upd, AVL_PTR_SIZE);},
        [&tio, &c_right, F_pc_r, ptr_upd](yield_t &yield)
        { mpc_select(tio, yield, c_right, F_pc_r, c_right, ptr_upd, AVL_PTR_SIZE);});

    setAVLLeftPtr(gp_pointers, gp_left);
    setAVLRightPtr(gp_pointers, gp_right);
    setAVLLeftPtr(p_pointers, p_left);
    setAVLRightPtr(p_pointers, p_right);
    setAVLLeftPtr(c_pointers, c_left);
    setAVLRightPtr(c_pointers, c_right);
}


/*
  If F_rs: (bal_upd & right_child)
    bal_l, balanced, bal_r, imbalance
    And then right shift to get imbalance bit, and new bal_l, bal_r bits
  else if F_ls: (bal_upd & left_child)
    imbalance, bal_l, balanced, bal_r
    And then left shift to get imbalance bit, and new bal_l, bal_r bits

*/
std::tuple<RegBS, RegBS, RegBS, RegBS> AVL::updateBalanceIns(MPCTIO &tio, yield_t &yield,
        RegBS bal_l, RegBS bal_r, RegBS bal_upd, RegBS child_dir) {
    bool player0 = tio.player()==0;
    RegBS s0;
    RegBS F_rs, F_ls, balanced, imbalance, nt_child_dir;

    // balanced = is the node currently balanced
    balanced = bal_l ^ bal_r;
    nt_child_dir = child_dir;
    if(player0){
        nt_child_dir^=1;
    }
    if(player0) {
        balanced^=1;
    }
    run_coroutines(tio, [&tio, &F_rs, child_dir, bal_upd](yield_t &yield)
        { //F_rs (Flag right shift) <- child_dir & bal_upd
          mpc_and(tio, yield, F_rs, child_dir, bal_upd);},
        [&tio, &F_ls, nt_child_dir, bal_upd](yield_t &yield)
        { //F_ls (Flag left shift) <- !child_dir & bal_upd
          mpc_and(tio, yield, F_ls, nt_child_dir, bal_upd);});


    std::vector<coro_t> coroutines;
    // Right shift if child_dir = 1 & bal_upd = 1
    coroutines.emplace_back(
        [&tio, &imbalance, F_rs, bal_r, balanced](yield_t &yield) {
            mpc_select(tio, yield, imbalance, F_rs, imbalance, bal_r);
        });
    coroutines.emplace_back(
        [&tio, &bal_r, F_rs, balanced](yield_t &yield) {
            mpc_select(tio, yield, bal_r, F_rs, bal_r, balanced);
        });
    coroutines.emplace_back(
        [&tio, &balanced, F_rs, bal_l](yield_t &yield) {
            mpc_select(tio, yield, balanced, F_rs, balanced, bal_l);
        });
    coroutines.emplace_back(
        [&tio, &bal_l, F_rs, s0](yield_t &yield) {
            mpc_select(tio, yield, bal_l, F_rs, bal_l, s0);
        });
    run_coroutines(tio, coroutines);
    coroutines.clear();

    // Left shift if child_dir = 0 & bal_upd = 1
    coroutines.emplace_back(
        [&tio, &imbalance, F_ls, bal_l] (yield_t &yield) {
            mpc_select(tio, yield, imbalance, F_ls, imbalance, bal_l);
        });
    coroutines.emplace_back(
        [&tio, &bal_l, F_ls, balanced] (yield_t &yield) {
            mpc_select(tio, yield, bal_l, F_ls, bal_l, balanced);
        });
    coroutines.emplace_back(
        [&tio, &balanced, F_ls, bal_r] (yield_t &yield) {
            mpc_select(tio, yield, balanced, F_ls, balanced, bal_r);
        });
    coroutines.emplace_back(
        [&tio, &bal_r, F_ls, s0](yield_t &yield) {
            mpc_select(tio, yield, bal_r, F_ls, bal_r, s0);
        });
    run_coroutines(tio, coroutines);

    // bal_upd <- bal_upd ^ imbalance
    RegBS F_bu0;
    mpc_and(tio, yield, F_bu0, bal_upd, balanced);
    mpc_select(tio, yield, bal_upd, F_bu0, bal_upd, s0);
    mpc_select(tio, yield, bal_upd, imbalance, bal_upd, s0);
    return {bal_l, bal_r, bal_upd, imbalance};
}

/*
  In updateBalanceDel, the position of imbalance, and shift direction for both
  cases are inverted (from that of updateBalanceIns()), since a bal_upd on a child
  implies it reduced height.

  If F_rs: (bal_upd & right_child)
    imbalance, bal_l, balanced, bal_r
    And then left shift to get imbalance bit, and new bal_l, bal_r bits
  else if F_ls: (bal_upd & left_child)
    bal_l, balanced, bal_r, imbalance
    And then right shift to get imbalance bit, and new bal_l, bal_r bits

*/
std::tuple<RegBS, RegBS, RegBS, RegBS> AVL::updateBalanceDel(MPCTIO &tio, yield_t &yield,
        RegBS bal_l, RegBS bal_r, RegBS bal_upd, RegBS child_dir) {
    bool player0 = tio.player()==0;
    RegBS s0;
    RegBS F_rs, F_ls, balanced, imbalance, not_imbalance;
    RegBS nt_child_dir = child_dir;
    if(player0) {
        nt_child_dir^=1;
    }

    // balanced = is the node currently balanced
    balanced = bal_l ^ bal_r;
    if(player0) {
        balanced^=1;
    }

    //F_ls (Flag left shift) <- child_dir & bal_upd
    //F_rs (Flag right shift) <- !child_dir & bal_upd
    run_coroutines(tio, [&tio, &F_ls, child_dir, bal_upd](yield_t &yield)
        { mpc_and(tio, yield, F_ls, child_dir, bal_upd);},
        [&tio, &F_rs, nt_child_dir, bal_upd](yield_t &yield)
        { mpc_and(tio, yield, F_rs, nt_child_dir, bal_upd);});

    // Left shift if F_ls
    run_coroutines(tio, [&tio, &imbalance, F_ls, bal_l](yield_t &yield)
        { mpc_select(tio, yield, imbalance, F_ls, imbalance, bal_l);},
        [&tio, &bal_l, F_ls, balanced](yield_t &yield)
        { mpc_select(tio, yield, bal_l, F_ls, bal_l, balanced);},
        [&tio, &balanced, F_ls, bal_r](yield_t &yield)
        { mpc_select(tio, yield, balanced, F_ls, balanced, bal_r);},
        [&tio, &bal_r, F_ls, s0](yield_t &yield)
        { mpc_select(tio, yield, bal_r, F_ls, bal_r, s0);});

    // Right shift if F_rs
    run_coroutines(tio, [&tio, &imbalance, F_rs, bal_r](yield_t &yield)
        { mpc_select(tio, yield, imbalance, F_rs, imbalance, bal_r);},
        [&tio, &bal_r, F_rs, balanced](yield_t &yield)
        { mpc_select(tio, yield, bal_r, F_rs, bal_r, balanced);},
        [&tio, &balanced, F_rs, bal_l](yield_t &yield)
        { mpc_select(tio, yield, balanced, F_rs, balanced, bal_l);},
        [&tio, &bal_l, F_rs, s0](yield_t &yield)
        { mpc_select(tio, yield, bal_l, F_rs, bal_l, s0);});

    /*
       if(bal_upd) and this node:
        (i) becomes balanced: the height has decreased, so continue propogating bal_upd.
        (ii) becomes imbalanced: fixImbalance will update bal_upd correctly.
        (iii) updates from balanced to left/right heavy: the height of this subtree has not changed,
              so don't propogate bal_upd.
        We handle (iii) below.
    */
    RegBS LR_heavy, bu0;
    LR_heavy = bal_l ^ bal_r;
    mpc_and(tio, yield, bu0, bal_upd, LR_heavy);
    mpc_select(tio, yield, bal_upd, bu0, bal_upd, s0);

    return {bal_l, bal_r, bal_upd, imbalance};
}

/*
    The recurisve AVL insert function.
    Takes as input: the current node pointer of the tree traversal (ptr),
    the address of the newly inserted node (ins_addr), the insertion key
    (insert_key), the underlying DORAM as a flat (A), the time-to-live (TTL),
    a flag indicating if this is a dummy operation (isDummy), and a return
    structure (ret) that gets stores the imbalance state (if any) during
    the insertion, to resolve it with a one time imbalance fix operation.

    Returns a tuple<RegBS a, RegBS b, RegBS c, RegBS d>
    where (a) is the balance update bit from the subtree, (b) is a flag to
    indicate when to store the grandparent node in the return structure,
    (c) is the pointer to the recursive subtree, and (d) is the direction of
    the subtree from the parent.
*/
std::tuple<RegBS, RegBS, RegXS, RegBS> AVL::insert(MPCTIO &tio, yield_t &yield, RegXS ptr, RegXS ins_addr,
    RegAS insert_key, Duoram<Node>::Flat &A, int TTL, RegBS isDummy, avl_insert_return &ret) {
    if(TTL==0) {
        RegBS z;
        return {z, z, z, z};
    }

    RegBS isReal = isDummy ^ (!tio.player());
    Node cnode;
    #ifdef AVL_OPT_ON
        nbits_t width = ceil(log2(cur_max_index+1));
        typename Duoram<Node>::template OblivIndex<RegXS,1> oidx(tio, yield, ptr, width);
        cnode = A[oidx];
        RegXS old_pointers = cnode.pointers;
    #else
        cnode = A[ptr];
    #endif

    // Compare key
    auto [lteq, gt] = compare_keys(tio, yield, cnode.key, insert_key);

    // Depending on [lteq, gt] select the next_ptr
    RegXS next_ptr;
    RegXS left = getAVLLeftPtr(cnode.pointers);
    RegXS right = getAVLRightPtr(cnode.pointers);
    RegBS bal_l = getLeftBal(cnode.pointers);
    RegBS bal_r = getRightBal(cnode.pointers);

    /*
    size_t rec_left = mpc_reconstruct(tio, yield, left, AVL_PTR_SIZE);
    size_t rec_right = mpc_reconstruct(tio, yield, right, AVL_PTR_SIZE);
    size_t rec_key = mpc_reconstruct(tio, yield, cnode.key, 64);
    printf("\n\n(Before recursing) Key = %ld\n", rec_key);
    printf("rec_left = %ld, rec_right = %ld\n", rec_left, rec_right);
    */

    mpc_select(tio, yield, next_ptr, gt, left, right, AVL_PTR_SIZE);
    /*
    size_t rec_next_ptr = mpc_reconstruct(tio, yield, next_ptr, AVL_PTR_SIZE);
    printf("rec_next_ptr = %ld\n", rec_next_ptr);
    */

    CDPF dpf = tio.cdpf(yield);
    size_t &aes_ops = tio.aes_ops();
    // F_z: Check if this is last node on path
    RegBS F_z = dpf.is_zero(tio, yield, next_ptr, aes_ops);
    RegBS F_i;

    // F_i: If this was last node on path (F_z), and isReal insert.
    mpc_and(tio, yield, F_i, (isReal), F_z);

    isDummy^=F_i;
    auto [bal_upd, F_gp, prev_node, prev_dir] = insert(tio, yield,
          next_ptr, ins_addr, insert_key, A, TTL-1, isDummy, ret);
    /*
    rec_bal_upd = mpc_reconstruct(tio, yield, bal_upd);
    rec_F_gp = mpc_reconstruct(tio, yield, F_gp);
    printf("Insert returns: rec_bal_upd = %d, rec_F_gp = %d\n",
          rec_bal_upd, rec_F_gp);
    size_t rec_ptr = mpc_reconstruct(tio, yield, pt);
    printf("\nrec_ptr = %ld\n", rec_ptr);
    */

    // Update balance
    // If we inserted at this level (F_i), bal_upd is set to 1
    mpc_or(tio, yield, bal_upd, bal_upd, F_i);
    auto [new_bal_l, new_bal_r, new_bal_upd, imbalance] = updateBalanceIns(tio, yield, bal_l, bal_r, bal_upd, gt);

    // Store if this insert triggers an imbalance
    ret.imbalance ^= imbalance;

    std::vector<coro_t> coroutines;
    // Save grandparent pointer
    coroutines.emplace_back(
        [&tio, &ret, F_gp, ptr](yield_t &yield) {
            mpc_select(tio, yield, ret.gp_node, F_gp, ret.gp_node, ptr, AVL_PTR_SIZE);
        });
    coroutines.emplace_back(
        [&tio, &ret, F_gp, gt](yield_t &yield) {
            mpc_select(tio, yield, ret.dir_gpp, F_gp, ret.dir_gpp, gt);
        });
    // Save parent pointer
    coroutines.emplace_back(
        [&tio, &ret, imbalance, ptr](yield_t &yield) {
            mpc_select(tio, yield, ret.p_node, imbalance, ret.p_node, ptr, AVL_PTR_SIZE);
        });
    coroutines.emplace_back(
        [&tio, &ret, imbalance, gt](yield_t &yield) {
            mpc_select(tio, yield, ret.dir_pc, imbalance, ret.dir_pc, gt);
        });
    // Save child pointer
    coroutines.emplace_back(
        [&tio, &ret, imbalance, prev_node](yield_t &yield) {
            mpc_select(tio, yield, ret.c_node, imbalance, ret.c_node, prev_node, AVL_PTR_SIZE);
        });
    coroutines.emplace_back(
        [&tio, &ret, imbalance, prev_dir](yield_t &yield) {
            mpc_select(tio, yield, ret.dir_cn, imbalance, ret.dir_cn, prev_dir);
        });
    run_coroutines(tio, coroutines);


    // Store new_bal_l and new_bal_r for this node
    setLeftBal(cnode.pointers, new_bal_l);
    setRightBal(cnode.pointers, new_bal_r);
    // We have to write the node pointers anyway to handle balance updates,
    // so we perform insertion along with it by modifying pointers appropriately.
    RegBS F_ir, F_il;
    run_coroutines(tio, [&tio, &F_ir, F_i, gt](yield_t &yield)
        { mpc_and(tio, yield, F_ir, F_i, gt); },
        [&tio, &F_il, F_i, lteq](yield_t &yield)
        { mpc_and(tio, yield, F_il, F_i, lteq); });

    run_coroutines(tio, [&tio, &left, F_il, ins_addr](yield_t &yield)
        { mpc_select(tio, yield, left, F_il, left, ins_addr);},
        [&tio, &right, F_ir, ins_addr](yield_t &yield)
        { mpc_select(tio, yield, right, F_ir, right, ins_addr);});

    setAVLLeftPtr(cnode.pointers, left);
    setAVLRightPtr(cnode.pointers, right);

    /*
    bool rec_F_ir, rec_F_il;
    rec_F_ir = mpc_reconstruct(tio, yield, F_ir);
    rec_F_il = mpc_reconstruct(tio, yield, F_il);
    rec_left = mpc_reconstruct(tio, yield, left, AVL_PTR_SIZE);
    rec_right = mpc_reconstruct(tio, yield, right, AVL_PTR_SIZE);
    printf("(After recursing) F_il = %d, left = %ld, F_ir = %d, right = %ld\n",
        rec_F_il, rec_left, rec_F_ir, rec_right);
    */

    #ifdef AVL_OPT_ON
        A[oidx].NODE_POINTERS+=(cnode.pointers - old_pointers);
    #else
        A[ptr].NODE_POINTERS = cnode.pointers;
    #endif
    // s0 = shares of 0
    RegBS s0;

    // If there was an imbalance then we need to store the grandparent node
    // (node in the level above) into the ret_struct. So we return imbalance.
    return {new_bal_upd, imbalance, ptr, gt};
}

/*
    Main AVL insert function.
    Takes as input the new node to insert.
*/

// Insert(root, ptr, key, TTL, isDummy) -> (new_ptr, wptr, wnode, f_p)
void AVL::insert(MPCTIO &tio, yield_t &yield, const Node &node) {
    bool player0 = tio.player()==0;
    // If there are no items in tree. Make this new item the root.
    if(num_items==0) {
        auto A = oram.flat(tio, yield);
        Node zero;
        A[0] = zero;
        A[1] = node;
        // Set root to a secret sharing of the constant value 1
        root.set(1*tio.player());
        num_items++;
        cur_max_index++;
        return;
    } else {
        // Insert node into next free slot in the ORAM
        int new_id;
        RegXS insert_address;
        num_items++;
        int TTL = AVL_TTL(num_items);
        bool insertAtEmptyLocation = (empty_locations.size() > 0);
        if(!insertAtEmptyLocation) {
            cur_max_index++;
        }
        auto A = oram.flat(tio, yield, 0, cur_max_index+1);
        if(insertAtEmptyLocation) {
            insert_address = empty_locations.back();
            empty_locations.pop_back();
            A[insert_address] = node;
        } else {
            new_id = num_items;
            A[new_id] = node;
            insert_address.set(new_id * tio.player());
        }

        RegBS isDummy;
        avl_insert_return ret;
        RegAS insert_key = node.key;
        // Recursive insert function
        auto [bal_upd, F_gp, prev_node, prev_dir] = insert(tio, yield, root,
            insert_address, insert_key, A, TTL, isDummy, ret);

        /*
        // Debug code
        bool rec_bal_upd, rec_F_gp, ret_dir_pc, ret_dir_cn;
        rec_bal_upd = mpc_reconstruct(tio, yield, bal_upd);
        rec_F_gp = mpc_reconstruct(tio, yield, F_gp);
        ret_dir_pc = mpc_reconstruct(tio, yield, ret.dir_pc);
        ret_dir_cn = mpc_reconstruct(tio, yield, ret.dir_cn);
        printf("(Top level) Insert returns: rec_bal_upd = %d, rec_F_gp = %d\n",
              rec_bal_upd, rec_F_gp);
        printf("(Top level) Insert returns: ret.dir_pc = %d, rt.dir_cn = %d\n",
              ret_dir_pc, ret_dir_cn);
        */

        // Perform balance procedure
        RegXS gp_pointers, parent_pointers, child_pointers;
        std::vector<coro_t> coroutines;
        #ifdef AVL_OPT_ON
            nbits_t width = ceil(log2(cur_max_index+1));
            typename Duoram<Node>::template OblivIndex<RegXS,1> oidx_gp(tio, yield, ret.gp_node, width);
            typename Duoram<Node>::template OblivIndex<RegXS,1> oidx_p(tio, yield, ret.p_node, width);
            typename Duoram<Node>::template OblivIndex<RegXS,1> oidx_c(tio, yield, ret.c_node, width);

            coroutines.emplace_back(
                [&tio, &A, &oidx_gp, &gp_pointers](yield_t &yield) {
                  auto acont = A.context(yield);
                  gp_pointers = acont[oidx_gp].NODE_POINTERS;});
            coroutines.emplace_back(
                [&tio, &A, &oidx_p, &parent_pointers](yield_t &yield) {
                  auto acont = A.context(yield);
                  parent_pointers = acont[oidx_p].NODE_POINTERS;});
            coroutines.emplace_back(
                [&tio, &A, &oidx_c, &child_pointers](yield_t &yield) {
                  auto acont = A.context(yield);
                  child_pointers = acont[oidx_c].NODE_POINTERS;});
            run_coroutines(tio, coroutines);
            coroutines.clear();

            /*
            gp_pointers = A[oidx_gp].NODE_POINTERS;
            parent_pointers = A[oidx_p].NODE_POINTERS;
            child_pointers = A[oidx_c].NODE_POINTERS;
            */
            /*
            size_t rec_gp_key = mpc_reconstruct(tio, yield, A[oidx_gp].NODE_KEY);
            size_t rec_p_key = mpc_reconstruct(tio, yield, A[oidx_p].NODE_KEY);
            size_t rec_c_key = mpc_reconstruct(tio, yield, A[oidx_c].NODE_KEY);
            size_t rec_gp_lptr = mpc_reconstruct(tio, iyield, getAVLLeftPtr(A[oidx_gp].NODE_POINTERS), AVL_PTR_SIZE);
            size_t rec_gp_rptr = mpc_reconstruct(tio, yield, getAVLRightPtr(A[oidx_gp].NODE_POINTERS), AVL_PTR_SIZE);
            size_t rec_p_lptr = mpc_reconstruct(tio, yield, getAVLLeftPtr(A[oidx_p].NODE_POINTERS), AVL_PTR_SIZE);
            size_t rec_p_rptr = mpc_reconstruct(tio, yield, getAVLRightPtr(A[oidx_p].NODE_POINTERS), AVL_PTR_SIZE);
            size_t rec_c_lptr = mpc_reconstruct(tio, yield, getAVLLeftPtr(A[oidx_c].NODE_POINTERS), AVL_PTR_SIZE);
            size_t rec_c_rptr = mpc_reconstruct(tio, yield, getAVLRightPtr(A[oidx_c].NODE_POINTERS), AVL_PTR_SIZE);
            printf("Reconstructed:\ngp_key = %ld, gp_left_ptr = %ld, gp_right_ptr = %ld\n",
                rec_gp_key, rec_gp_lptr, rec_gp_rptr);
            printf("p_key = %ld, p_left_ptr = %ld, p_right_ptr = %ld\n",
                rec_p_key, rec_p_lptr, rec_p_rptr);
            printf("c_key = %ld, c_left_ptr = %ld, c_right_ptr = %ld\n",
                rec_c_key, rec_c_lptr, rec_c_rptr);
            */
        #else
            gp_pointers = A[ret.gp_node].NODE_POINTERS;
            parent_pointers = A[ret.p_node].NODE_POINTERS;
            child_pointers = A[ret.c_node].NODE_POINTERS;
        #endif
        // n_node (child's next node)
        RegXS child_left = getAVLLeftPtr(child_pointers);
        RegXS child_right = getAVLRightPtr(child_pointers);
        RegXS n_node, n_pointers;
        mpc_select(tio, yield, n_node, ret.dir_cn, child_left, child_right, AVL_PTR_SIZE);

        #ifdef AVL_OPT_ON
            typename Duoram<Node>::template OblivIndex<RegXS,1> oidx_n(tio, yield, n_node, width);
            n_pointers = A[oidx_n].NODE_POINTERS;
        #else
            n_pointers = A[n_node].NODE_POINTERS;
        #endif

        #ifdef AVL_OPT_ON
            RegXS old_gp_pointers, old_parent_pointers, old_child_pointers, old_n_pointers;
            old_gp_pointers = gp_pointers;
            old_parent_pointers = parent_pointers;
            old_child_pointers = child_pointers;
            old_n_pointers = n_pointers;
        #endif

        // F_dr = (dir_pc != dir_cn) : i.e., double rotation case if
        // (parent->child) and (child->new_node) are not in the same direction
        RegBS F_dr = (ret.dir_pc) ^ (ret.dir_cn);

        /* Flags:  F_cn_rot = child->node rotate
                   F_ur = update root.

           In case of an imbalance we have to always rotate p->c link. (L or R case)
           In case of an imbalance where p->c and c->n are in different directions, we have
           to perform a double rotation (LR or RL case). In such cases, first rotate
           c->n link, and then p->c link
           (Note: in the second rotation c is actually n, since the the first rotation
            swaps their positions)
        */
        RegBS F_cn_rot, F_ur, s0;
        run_coroutines(tio, [&tio, &F_ur, F_gp, ret](yield_t &yield)
            {mpc_and(tio, yield, F_ur, F_gp, ret.imbalance);},
            [&tio, &F_cn_rot, ret, F_dr](yield_t &yield)
            {mpc_and(tio, yield, F_cn_rot, ret.imbalance, F_dr);});

        // Get the n children information for 2nd rotate fix before rotations happen.
        RegBS n_bal_l, n_bal_r;
        RegXS n_l = getAVLLeftPtr(n_pointers);
        RegXS n_r = getAVLRightPtr(n_pointers);
        n_bal_l = getLeftBal(n_pointers);
        n_bal_r = getRightBal(n_pointers);

        // First rotation: c->n link
        rotate(tio, yield, parent_pointers, ret.c_node, child_pointers, n_node,
            n_pointers, ret.dir_pc, ret.dir_cn, F_cn_rot, s0);

        // If F_cn_rot, i.e. we did first rotation. Then c and n need to swap before the second rotate.
        RegXS new_child_pointers, new_child;

        run_coroutines(tio, [&tio, &new_child_pointers, F_cn_rot, child_pointers, n_pointers] (yield_t &yield)
            {mpc_select(tio, yield, new_child_pointers, F_cn_rot, child_pointers, n_pointers);},
            [&tio, &new_child, F_cn_rot, ret, n_node](yield_t &yield)
            {mpc_select(tio, yield, new_child, F_cn_rot, ret.c_node, n_node, AVL_PTR_SIZE);});

        // Second rotation: p->c link
        rotate(tio, yield, gp_pointers, ret.p_node, parent_pointers, new_child,
            new_child_pointers, ret.dir_gpp, ret.dir_pc, ret.imbalance, F_gp);

        // Set parent and child balances to 0 if there was an imbalance.
        // parent balances are already set to 0 from updateBalanceIns
        RegBS temp_bal, p_bal_l, p_bal_r, p_bal_ndpc;
        RegBS c_bal_l, c_bal_r, c_bal_dpc, n_bal_dpc, n_bal_ndpc;
        p_bal_l = getLeftBal(parent_pointers);
        p_bal_r = getRightBal(parent_pointers);

        run_coroutines(tio, [&tio, &child_pointers, F_cn_rot, new_child_pointers] (yield_t &yield)
            {mpc_select(tio, yield, child_pointers, F_cn_rot, new_child_pointers, child_pointers);},
            [&tio, &n_pointers, F_cn_rot, new_child_pointers] (yield_t &yield)
            {mpc_select(tio, yield, n_pointers, F_cn_rot, n_pointers, new_child_pointers);});

        c_bal_l = getLeftBal(child_pointers);
        c_bal_r = getRightBal(child_pointers);

        run_coroutines(tio, [&tio, &c_bal_l, ret, s0] (yield_t &yield)
            {mpc_select(tio, yield, c_bal_l, ret.imbalance, c_bal_l, s0);},
            [&tio, &c_bal_r, ret, s0] (yield_t &yield)
            {mpc_select(tio, yield, c_bal_r, ret.imbalance, c_bal_r, s0);});

        /*   In the double rotation case: balance of c and p have a tweak
           p_bal_ndpc <- !(n_bal_ndpc)
           c_bal_dpc <- !(n_bal_dpc) */
        size_t &aes_ops = tio.aes_ops();

        RegBS n_l0, n_r0;
        run_coroutines(tio, [&tio, &n_l0, n_l, &aes_ops] (yield_t &yield)
            { CDPF cdpf = tio.cdpf(yield);
              n_l0 = cdpf.is_zero(tio, yield, n_l, aes_ops);},
            [&tio, &n_r0, n_r, &aes_ops] (yield_t &yield)
            { CDPF cdpf = tio.cdpf(yield);
              n_r0 = cdpf.is_zero(tio, yield, n_r, aes_ops);});

        RegBS p_c_update, n_has_children;
        // n_has_children = !(n_l0 & n_r0)
        mpc_and(tio, yield, n_has_children, n_l0, n_r0);
        if(player0) {
            n_has_children^=1;
        }

        run_coroutines(tio, [&tio, &p_c_update, F_cn_rot, n_has_children] (yield_t &yield)
            {mpc_and(tio, yield, p_c_update, F_cn_rot, n_has_children);},
            [&tio, &n_bal_ndpc, ret, n_bal_l, n_bal_r] (yield_t &yield)
            {mpc_select(tio, yield, n_bal_ndpc, ret.dir_pc, n_bal_r, n_bal_l);},
            [&tio, &n_bal_dpc, ret, n_bal_l, n_bal_r] (yield_t &yield)
            {mpc_select(tio, yield, n_bal_dpc, ret.dir_pc, n_bal_l, n_bal_r);},
            [&tio, &p_bal_ndpc, ret, p_bal_r, p_bal_l] (yield_t &yield)
            {mpc_select(tio, yield, p_bal_ndpc, ret.dir_pc, p_bal_r, p_bal_l);});

        // !n_bal_ndpc, !n_bal_dpc
        if(player0) {
            n_bal_ndpc^=1;
            n_bal_dpc^=1;
        }

        run_coroutines(tio, [&tio, &p_bal_ndpc, p_c_update, n_bal_ndpc] (yield_t &yield)
            {mpc_select(tio, yield, p_bal_ndpc, p_c_update, p_bal_ndpc, n_bal_ndpc);},
            [&tio, &c_bal_dpc, p_c_update, n_bal_dpc] (yield_t &yield)
            {mpc_select(tio, yield, c_bal_dpc, p_c_update, c_bal_dpc, n_bal_dpc);});

        coroutines.emplace_back([&tio, &p_bal_r, ret, p_bal_ndpc] (yield_t &yield)
            {mpc_select(tio, yield, p_bal_r, ret.dir_pc, p_bal_ndpc, p_bal_r);});
        coroutines.emplace_back([&tio, &p_bal_l, ret, p_bal_ndpc] (yield_t &yield)
            {mpc_select(tio, yield, p_bal_l, ret.dir_pc, p_bal_l, p_bal_ndpc);});
        coroutines.emplace_back([&tio, &c_bal_r, ret, c_bal_dpc] (yield_t &yield)
            {mpc_select(tio, yield, c_bal_r, ret.dir_pc, c_bal_r, c_bal_dpc);});
        coroutines.emplace_back([&tio, &c_bal_l, ret, c_bal_dpc] (yield_t &yield)
            {mpc_select(tio, yield, c_bal_l, ret.dir_pc, c_bal_dpc, c_bal_l);});
        // If double rotation (LR/RL) case, n ends up with 0 balance.
        // In all other cases, n's balance remains unaffected by rotation during insertion.
        coroutines.emplace_back([&tio, &n_bal_l, F_cn_rot, s0] (yield_t &yield)
            {mpc_select(tio, yield, n_bal_l, F_cn_rot, n_bal_l, s0);});
        coroutines.emplace_back([&tio, &n_bal_r, F_cn_rot, s0] (yield_t &yield)
            {mpc_select(tio, yield, n_bal_r, F_cn_rot, n_bal_r, s0);});
        run_coroutines(tio, coroutines);

        setLeftBal(parent_pointers, p_bal_l);
        setRightBal(parent_pointers, p_bal_r);
        setLeftBal(child_pointers, c_bal_l);
        setRightBal(child_pointers, c_bal_r);
        setLeftBal(n_pointers, n_bal_l);
        setRightBal(n_pointers, n_bal_r);

        // Write back update pointers and balances into gp, p, c, and n
        #ifdef AVL_OPT_ON
            A[oidx_n].NODE_POINTERS+=(n_pointers - old_n_pointers);
            A[oidx_c].NODE_POINTERS+=(child_pointers - old_child_pointers);
            A[oidx_p].NODE_POINTERS+=(parent_pointers - old_parent_pointers);
            A[oidx_gp].NODE_POINTERS+=(gp_pointers - old_gp_pointers);
        #else
            A[ret.c_node].NODE_POINTERS = child_pointers;
            A[ret.p_node].NODE_POINTERS = parent_pointers;
            A[ret.gp_node].NODE_POINTERS = gp_pointers;
            A[n_node].NODE_POINTERS = n_pointers;
        #endif

        // Handle root pointer update (if F_ur is true)
        // If F_ur and we did a double rotation: root <-- new node
        // If F_ur and we did a single rotation: root <-- child node
        RegXS temp_root = root;
        run_coroutines(tio, [&tio, &temp_root, F_ur, ret] (yield_t &yield)
            {mpc_select(tio, yield, temp_root, F_ur, temp_root, ret.c_node, AVL_PTR_SIZE);},
            [&tio, &F_ur, F_gp, F_dr] (yield_t &yield)
            {mpc_and(tio, yield, F_ur, F_gp, F_dr);});

        mpc_select(tio, yield, temp_root, F_ur, temp_root, n_node, AVL_PTR_SIZE);
        root = temp_root;
    }
}


bool AVL::lookup(MPCTIO &tio, yield_t &yield, RegXS ptr, RegAS key, Duoram<Node>::Flat &A,
    int TTL, RegBS isDummy, Node *ret_node) {
    if(TTL==0) {
        // Reconstruct and return isDummy
        // If we found the key, then isDummy will be true
        bool found = reconstruct_RegBS(tio, yield, isDummy);
        return found;
    }

    RegBS isNotDummy = isDummy ^ (!tio.player());
    Node cnode = A[ptr];
    // Compare key
    CDPF cdpf = tio.cdpf(yield);
    auto [lt, eq, gt] = cdpf.compare(tio, yield, key - cnode.key, tio.aes_ops());

    // Depending on [lteq, gt] select the next ptr/index as
    // first AVL_PTR_SIZE bits of cnode.pointers if lteq
    // next AVL_PTR_SIZE bits of cnode.pointers if gt
    // (the last 2 bits are balance bits)
    RegXS left = getAVLLeftPtr(cnode.pointers);
    RegXS right = getAVLRightPtr(cnode.pointers);

    RegXS next_ptr;
    mpc_select(tio, yield, next_ptr, gt, left, right, 32);

    RegBS F_found;
    // If we haven't found the key yet, and the lookup matches the current node key,
    // then we found the node to return

    run_coroutines(tio,
        [&tio, &F_found, isNotDummy, eq](yield_t &yield)
        { mpc_and(tio, yield, F_found, isNotDummy, eq);},
        [&tio, &ret_node, F_found, &cnode](yield_t &yield)
        { mpc_select(tio, yield, ret_node->key, F_found, ret_node->key, cnode.key);},
        [&tio, &ret_node, F_found, &cnode](yield_t &yield)
        { mpc_select(tio, yield, ret_node->value, F_found, ret_node->value, cnode.value);});

    isDummy^=F_found;
    bool found = lookup(tio, yield, next_ptr, key, A, TTL-1, isDummy, ret_node);

    return found;
}

bool AVL::lookup(MPCTIO &tio, yield_t &yield, RegAS key, Node *ret_node) {
    auto A = oram.flat(tio, yield);
    RegBS isDummy;
    bool found = lookup(tio, yield, root, key, A, num_items, isDummy, ret_node);
    return found;
}

void AVL::updateChildPointers(MPCTIO &tio, yield_t &yield, RegXS &left, RegXS &right,
          RegBS c_prime, const avl_del_return &ret_struct) {
    bool player0 = tio.player()==0;
    RegBS F_rr; // Flag to resolve F_r by updating right child ptr
    RegBS F_rl; // Flag to resolve F_r by updating left child ptr
    RegBS nt_c_prime = c_prime;
    if(player0)
        nt_c_prime^=1;

    run_coroutines(tio, [&tio, &F_rr, c_prime, ret_struct](yield_t &yield)
        { mpc_and(tio, yield, F_rr, c_prime, ret_struct.F_r);},
        [&tio, &F_rl, nt_c_prime, ret_struct](yield_t &yield)
        { mpc_and(tio, yield, F_rl, nt_c_prime, ret_struct.F_r);});

    run_coroutines(tio, [&tio, &right, F_rr, ret_struct](yield_t &yield)
        { mpc_select(tio, yield, right, F_rr, right, ret_struct.ret_ptr);},
        [&tio, &left, F_rl, ret_struct](yield_t &yield)
        { mpc_select(tio, yield, left, F_rl, left, ret_struct.ret_ptr);});
}


// Perform rotations if imbalance (else dummy rotations)
/*
   For capturing both the symmetric L and R cases of rotations, we'll capture directions with
   dpc  = dir_pc = direction from parent to child, and
   ndpc = not(dir_pc)
   When we travelled down the stack, we went from p->c. But in deletions to handle any imbalance
   we look at c's sibling cs (child's sibling). And the rotation is between p and cs if there
   was an imbalance at p, and perhaps even cs and its child (the child in dir_pc, as that's the
   only case that results in a double rotation when deleting).

   In case of an imbalance we have to always rotate p->cs link. (L or R case)
   If cs.bal_(dir_pc), then we have a double rotation (LR or RL) case.
   In such cases, first rotate cs->gcs link, and then p->cs link. gcs = grandchild on cs path

   Layout: In the R (or LR) case:

         p
       /   \
      cs    c
     /  \
    a   gcs
        /  \
       x    y

   - One of x or y must exist for it to be an LR case,
     since then cs.bal_(dir_pc) = cs.bal_r = 1

   Layout: In the L (or RL) case:

         p
       /   \
      c     cs
           /  \
         gcs   a
        /   \
       x     y

   - One of x or y must exist for it to be an RL case,
     since then cs.bal_(dir_pc) = cs.bal_l = 1

   (Note: if double rotation case, in the second rotation cs is actually gcs,
    since the the first rotation swaps their positions)
*/

void AVL::fixImbalance(MPCTIO &tio, yield_t &yield, Duoram<Node>::Flat &A,
        Duoram<Node>::OblivIndex<RegXS, 1> oidx, RegXS oidx_oldptrs, RegXS ptr,
        RegXS nodeptrs, RegBS new_p_bal_l, RegBS new_p_bal_r, RegBS &bal_upd,
        RegBS c_prime, RegXS cs_ptr, RegBS imb, RegBS &F_ri,
        avl_del_return &ret_struct) {

    bool player0 = tio.player()==0;
    RegBS s0, s1;
    s1.set(tio.player()==1);

    Node cs_node, gcs_node;
    #ifdef AVL_OPT_ON
        RegXS old_cs_ptr, old_gcs_ptr;
        nbits_t width = ceil(log2(cur_max_index+1));
        typename Duoram<Node>::template OblivIndex<RegXS,1> oidx_cs(tio, yield, cs_ptr, width);
        cs_node = A[oidx_cs];
            old_cs_ptr = cs_node.pointers;
    #else
        cs_node = A[cs_ptr];
    #endif
    //dirpc = dir_pc = dpc = c_prime
    RegBS cs_bal_l, cs_bal_r, cs_bal_dpc, cs_bal_ndpc, p_bal_ndpc, p_bal_dpc;
    RegBS F_dr, not_c_prime;
    RegXS gcs_ptr, cs_left, cs_right, cs_dpc, cs_ndpc, null;

    not_c_prime = c_prime;
    if(player0) {
      not_c_prime^=1;
    }

    // child's sibling node's balances in dir_pc (dpc), and not_dir_pc (ndpc)
    cs_bal_l = getLeftBal(cs_node.pointers);
    cs_bal_r = getRightBal(cs_node.pointers);
    cs_left = getAVLLeftPtr(cs_node.pointers);
    cs_right = getAVLRightPtr(cs_node.pointers);

    std::vector<coro_t> coroutines;
    RegBS gcs_balanced, gcs_bal_dpc, gcs_bal_ndpc;
    RegBS ndpc_is_l, ndpc_is_r, dpc_is_l, dpc_is_r;

    // First flags to check dpc = L/R, and similarly ndpc = L/R
    // If it's not an imbalance all of these are zeroes, resulting in no updates
    // to the pointers and balances in the end when we write back post imbalance
    // fix pointers and balances.
    coroutines.emplace_back([&tio, &ndpc_is_l, c_prime, imb] (yield_t &yield)
        { mpc_and(tio, yield, ndpc_is_l, imb, c_prime);});
    coroutines.emplace_back([&tio, &ndpc_is_r, imb, not_c_prime](yield_t &yield)
        { mpc_and(tio, yield, ndpc_is_r, imb, not_c_prime);});
    coroutines.emplace_back([&tio, &dpc_is_l, imb, not_c_prime](yield_t &yield)
        { mpc_and(tio, yield, dpc_is_l, imb, not_c_prime);});
    coroutines.emplace_back([&tio, &dpc_is_r, imb, c_prime](yield_t &yield)
        { mpc_and(tio, yield, dpc_is_r, imb, c_prime);});
    run_coroutines(tio, coroutines);
    coroutines.clear();

    coroutines.emplace_back(
        [&tio, &cs_bal_dpc, dpc_is_r, cs_bal_l, cs_bal_r] (yield_t &yield)
        { mpc_select(tio, yield, cs_bal_dpc, dpc_is_r, cs_bal_l, cs_bal_r);});
    coroutines.emplace_back(
        [&tio, &cs_bal_ndpc, ndpc_is_l, cs_bal_r, cs_bal_l](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_ndpc, ndpc_is_l, cs_bal_r, cs_bal_l);});
    coroutines.emplace_back(
        [&tio, &cs_dpc, dpc_is_r, cs_left, cs_right](yield_t &yield)
        { mpc_select(tio, yield, cs_dpc, dpc_is_r, cs_left, cs_right);});
    coroutines.emplace_back(
        [&tio, &cs_ndpc, ndpc_is_l, cs_right, cs_left](yield_t &yield)
        { mpc_select(tio, yield, cs_ndpc, ndpc_is_l, cs_right, cs_left);});
    coroutines.emplace_back(
        [&tio, &p_bal_ndpc, ndpc_is_r, new_p_bal_l, new_p_bal_r](yield_t &yield)
        { mpc_select(tio, yield, p_bal_ndpc, ndpc_is_r, new_p_bal_l, new_p_bal_r);});
    coroutines.emplace_back(
        [&tio, &p_bal_dpc, dpc_is_r, new_p_bal_l, new_p_bal_r] (yield_t &yield)
        { mpc_select(tio, yield, p_bal_dpc, dpc_is_r, new_p_bal_l, new_p_bal_r);});
    run_coroutines(tio, coroutines);
    coroutines.clear();

    // We need to double rotate (LR or RL case) if cs_bal_dpc is 1
    run_coroutines(tio, [&tio, &F_dr, imb, cs_bal_dpc] (yield_t &yield)
        { mpc_and(tio, yield, F_dr, imb, cs_bal_dpc);},
        [&tio, &gcs_ptr, cs_bal_dpc, cs_ndpc, cs_dpc](yield_t &yield)
        { mpc_select(tio, yield, gcs_ptr, cs_bal_dpc, cs_ndpc, cs_dpc, AVL_PTR_SIZE);});

    #ifdef AVL_OPT_ON
        typename Duoram<Node>::template OblivIndex<RegXS,1> oidx_gcs(tio, yield, gcs_ptr, width);
        gcs_node = A[oidx_gcs];
        old_gcs_ptr = gcs_node.pointers;
    #else
        gcs_node = A[gcs_ptr];
    #endif

    RegBS gcs_bal_l = getLeftBal(gcs_node.pointers);
    RegBS gcs_bal_r = getRightBal(gcs_node.pointers);

    run_coroutines(tio, [&tio, &gcs_bal_dpc, dpc_is_r, gcs_bal_l, gcs_bal_r](yield_t &yield)
        { mpc_select(tio, yield, gcs_bal_dpc, dpc_is_r, gcs_bal_l, gcs_bal_r);},
        [&tio, &gcs_bal_ndpc, ndpc_is_r, gcs_bal_l, gcs_bal_r](yield_t &yield)
        { mpc_select(tio, yield, gcs_bal_ndpc, ndpc_is_r, gcs_bal_l, gcs_bal_r);});

    // First rotation: cs->gcs link
    rotate(tio, yield, nodeptrs, cs_ptr, cs_node.pointers, gcs_ptr,
        gcs_node.pointers, not_c_prime, c_prime, F_dr, s0);

    // If F_dr, we did first rotation. Then cs and gcs need to swap before the second rotate.
    RegXS new_cs_pointers, new_cs, new_ptr;
    run_coroutines(tio, [&tio, &new_cs_pointers, F_dr, cs_node, gcs_node](yield_t &yield)
        { mpc_select(tio, yield, new_cs_pointers, F_dr, cs_node.pointers, gcs_node.pointers);},
        [&tio, &new_cs, F_dr, cs_ptr, gcs_ptr](yield_t &yield)
        { mpc_select(tio, yield, new_cs, F_dr, cs_ptr, gcs_ptr, AVL_PTR_SIZE);},
        [&tio, &new_ptr, F_dr, cs_ptr, gcs_ptr](yield_t &yield)
        { mpc_select(tio, yield, new_ptr, F_dr, cs_ptr, gcs_ptr);});

    // Second rotation: p->cs link
    // Since we don't have access to gp node here we just send a null and s0
    // for gp_pointers and dir_gpp. Instead this pointer fix is handled by F_r
    // and ret_struct.ret_ptr.
    rotate(tio, yield, null, ptr, nodeptrs, new_cs,
        new_cs_pointers, s0, not_c_prime, imb, s1);

    // If imb (we do some rotation), then update F_r, and ret_ptr, to
    // fix the gp->p link (There are F_r clauses later, but they are mutually
    // exclusive events. They will never trigger together.)

    F_ri = imb;
    coroutines.emplace_back([&tio, &ret_struct, imb, new_ptr](yield_t &yield) {
        mpc_select(tio, yield, ret_struct.ret_ptr, imb, ret_struct.ret_ptr, new_ptr);
    });
    // Write back new_cs_pointers correctly to (cs_node/gcs_node).pointers
    // and then balance the nodes
    coroutines.emplace_back([&tio, &cs_node, F_dr, new_cs_pointers](yield_t &yield) {
        mpc_select(tio, yield, cs_node.pointers, F_dr, new_cs_pointers, cs_node.pointers);
    });
    coroutines.emplace_back([&tio, &gcs_node, F_dr, new_cs_pointers](yield_t &yield) {
        mpc_select(tio, yield, gcs_node.pointers, F_dr, gcs_node.pointers, new_cs_pointers);
    });
    run_coroutines(tio, coroutines);
    coroutines.clear();

    /*
       Update balances based on imbalance and type of rotations that happen.
       In the case of an imbalance, updateBalance() sets bal_l and bal_r of p to 0.
    */
    RegBS IC1, IC2, IC3; // Imbalance Case 1, 2 or 3
    RegBS cs_zero_bal = cs_bal_dpc ^ cs_bal_ndpc;
    if(player0) {
        cs_zero_bal^=1;
    }
    run_coroutines(tio, [&tio, &IC1, imb, cs_bal_ndpc] (yield_t &yield) {
        // IC1 = Single rotation (L/R). L/R = dpc
            mpc_and(tio, yield, IC1, imb, cs_bal_ndpc);
        },
        // IC2 = Single rotation (L/R). L/R = dpc
        [&tio, &IC2, imb, cs_zero_bal](yield_t &yield) {
            mpc_and(tio, yield, IC2, imb, cs_zero_bal);
        },
        [&tio, &IC3, imb, cs_bal_dpc](yield_t &yield) {
        // IC3 = Double rotation (LR/RL). 1st rotate direction = ndpc, 2nd direction = dpc
            mpc_and(tio, yield, IC3, imb, cs_bal_dpc);
        });


    /* IC3 has 3 subcases:
          IC3_S1: gcs_bal_dpc = 0, gcs_bal_ndpc = 1
          IC3_S2: gcs_bal_dpc = 1, gc_bal_ndpc = 0
          IC3_S3: gcs_bal_dpc = 0, gcs_bal_ndpc = 0

          IC3_S1: p_dpc <- 1
                  cs_dpc <- 0
                  (gcs_bal stays same)
          IC3_S2: Swap cs_dpc and cs_ndpc (1 0 -> - 1).
                  cs_dpc <- 0, cs_ndpc <- 1
                  gcs_bal_dpc <- 0
          IC3_S3: cs_dpc <- 0
                  gcs_bal stays same
    */
    RegBS IC3_S1, IC3_S2, IC3_S3;
    gcs_balanced = gcs_bal_dpc ^ gcs_bal_ndpc;
    if(player0) {
        gcs_balanced^=1;
    }

    // Updating balance bits of p, cs, and gcs.
    // Parallel Ops 1
    coroutines.emplace_back([&tio, &cs_bal_ndpc, IC1, s0](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_ndpc, IC1, cs_bal_ndpc, s0);});
    coroutines.emplace_back([&tio, &cs_bal_dpc, IC2, s1](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_dpc, IC2, cs_bal_dpc, s1);});
    coroutines.emplace_back([&tio, &p_bal_ndpc, IC2, s1](yield_t &yield)
        { mpc_select(tio, yield, p_bal_ndpc, IC2, p_bal_ndpc, s1);});
    coroutines.emplace_back([&tio, &IC3_S1, IC3, gcs_bal_ndpc](yield_t &yield)
        { mpc_and(tio, yield, IC3_S1, IC3, gcs_bal_ndpc);});
    coroutines.emplace_back([&tio, &IC3_S2, IC3, gcs_bal_dpc](yield_t &yield)
        { mpc_and(tio, yield, IC3_S2, IC3, gcs_bal_dpc);});
    coroutines.emplace_back([&tio, &IC3_S3, IC3, gcs_balanced](yield_t &yield)
        { mpc_and(tio, yield, IC3_S3, IC3, gcs_balanced);});
    // In the IC2 case bal_upd = 0 (The rotation doesn't end up
    // decreasing height of this subtree.)
    coroutines.emplace_back([&tio, &bal_upd, IC2, s0](yield_t &yield)
        { mpc_select(tio, yield, bal_upd, IC2, bal_upd, s0);});
    run_coroutines(tio, coroutines);
    coroutines.clear();

    // Parallel Ops 2
    coroutines.emplace_back([&tio, &cs_bal_dpc, IC3, s0](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_dpc, IC3, cs_bal_dpc, s0);});
    coroutines.emplace_back([&tio, &p_bal_dpc, IC3_S1, s1](yield_t &yield)
        { mpc_select(tio, yield, p_bal_dpc, IC3_S1, p_bal_dpc, s1);});
    coroutines.emplace_back([&tio, &cs_bal_ndpc, IC3_S2, s1](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_ndpc, IC3_S2, cs_bal_ndpc, s1);});
    coroutines.emplace_back([&tio, &gcs_bal_dpc, IC3_S2, s0](yield_t &yield)
        { mpc_select(tio, yield, gcs_bal_dpc, IC3_S2, gcs_bal_dpc, s0);});
    run_coroutines(tio, coroutines);
    coroutines.clear();

    // Write back updated balance bits (Parallel batch 1)
    // Updating gcs_bal_l/r
    coroutines.emplace_back([&tio, &gcs_bal_r, dpc_is_r, gcs_bal_dpc](yield_t &yield)
        { mpc_select(tio, yield, gcs_bal_r, dpc_is_r, gcs_bal_r, gcs_bal_dpc);});
    coroutines.emplace_back([&tio, &gcs_bal_l, dpc_is_l, gcs_bal_dpc](yield_t &yield)
        { mpc_select(tio, yield, gcs_bal_l, dpc_is_l, gcs_bal_l, gcs_bal_dpc);});
    // Updating cs_bal_l/r (cs_bal_dpc effected by IC3, cs_bal_ndpc effected by IC1,2)
    coroutines.emplace_back([&tio, &cs_bal_r, dpc_is_r, cs_bal_dpc](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_r, dpc_is_r, cs_bal_r, cs_bal_dpc);});
    coroutines.emplace_back([&tio, &cs_bal_l, dpc_is_l, cs_bal_dpc](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_l, dpc_is_l, cs_bal_l, cs_bal_dpc);});
    // Updating new_p_bal_l/r (p_bal_ndpc effected by IC2)
    coroutines.emplace_back([&tio, &new_p_bal_r, ndpc_is_r, p_bal_ndpc] (yield_t &yield)
        { mpc_select(tio, yield, new_p_bal_r, ndpc_is_r, new_p_bal_r, p_bal_ndpc);});
    coroutines.emplace_back([&tio, &new_p_bal_l, ndpc_is_l, p_bal_ndpc](yield_t &yield)
        { mpc_select(tio, yield, new_p_bal_l, ndpc_is_l, new_p_bal_l, p_bal_ndpc);});
    run_coroutines(tio, coroutines);
    coroutines.clear();

    // Write back updated balance bits (Parallel batch 2)
    coroutines.emplace_back([&tio, &cs_bal_r, ndpc_is_r, cs_bal_ndpc] (yield_t &yield)
        { mpc_select(tio, yield, cs_bal_r, ndpc_is_r, cs_bal_r, cs_bal_ndpc);});
    coroutines.emplace_back([&tio, &cs_bal_l, ndpc_is_l, cs_bal_ndpc](yield_t &yield)
        { mpc_select(tio, yield, cs_bal_l, ndpc_is_l, cs_bal_l, cs_bal_ndpc);});
    run_coroutines(tio, coroutines);
    coroutines.clear();

    // Write back <cs_bal_dpc, cs_bal_ndpc> and <gcs_bal_l, gcs_bal_r>
    setLeftBal(gcs_node.pointers, gcs_bal_l);
    setRightBal(gcs_node.pointers, gcs_bal_r);
    setLeftBal(cs_node.pointers, cs_bal_l);
    setRightBal(cs_node.pointers, cs_bal_r);
    setLeftBal(nodeptrs, new_p_bal_l);
    setRightBal(nodeptrs, new_p_bal_r);

    // Write back updated pointers correctly accounting for rotations
    #ifdef AVL_OPT_ON
      coroutines.emplace_back(
          [&tio, &A, &oidx_cs, &cs_node, old_cs_ptr] (yield_t &yield) {
              auto acont = A.context(yield);
              (acont[oidx_cs].NODE_POINTERS)+= (cs_node.pointers - old_cs_ptr);});
      coroutines.emplace_back(
          [&tio, &A, &oidx_gcs, &gcs_node, old_gcs_ptr] (yield_t &yield) {
              auto acont = A.context(yield);
              (acont[oidx_gcs].NODE_POINTERS)+= (gcs_node.pointers - old_gcs_ptr);});
      coroutines.emplace_back(
          [&tio, &A, &oidx, nodeptrs, oidx_oldptrs] (yield_t &yield) {
              auto acont = A.context(yield);
              (acont[oidx].NODE_POINTERS)+=(nodeptrs - oidx_oldptrs);});
      run_coroutines(tio, coroutines);
      coroutines.clear();
    #else
      A[cs_ptr].NODE_POINTERS = cs_node.pointers;
      A[gcs_ptr].NODE_POINTERS = gcs_node.pointers;
      A[ptr].NODE_POINTERS = nodeptrs;
    #endif
}

/*
    Update the return structure

    F_dh = Delete Here flag,
    F_sf = successor found (no more left children while trying to find successor)
    F_r  = Flag for updating with ret_struct.ret_ptr. F_r happens in 3 cases.
           It's subflag F_rs, handles cases (i) and (ii).

    F_rs = Subflag of F_r. F_rs indicates if we need to update a child pointer
           at this level by skipping the current child in the direction of
           traversal. We do this in two cases (i) and (ii).

    F_r cases:
        (i) F_d & (!F_2) : If we delete here, and this node does not have
            2 children (;i.e., we are not in the finding successor case)
       (ii) F_sf: Found the successor (no more left children while
            traversing to find successor)

       In cases i and ii we skip the next node, and make the current node
       point to the node after the next node on the path.

      (iii) We did rotation(s) at the lower level, changing the child in
            that position. So we update it to the correct node in that
            position now.

   Whether skip happens or just update happens is handled by F_r and
   the ret_struct.ret_ptr that is set.
*/

void AVL::updateRetStruct(MPCTIO &tio, yield_t &yield, RegXS ptr, RegBS F_rs, RegBS F_dh,
          RegBS F_ri, RegBS &bal_upd, avl_del_return &ret_struct) {

    bool player0 = tio.player()==0;
    RegBS s0, s1;
    s1.set(tio.player()==1);

    // F_rs and F_ri will never trigger together. So the line below
    // set ret_ptr to the correct pointer to handle either case
    // If neither F_rs nor F_ri, we set the ret_ptr to current ptr.
    RegBS F_nr;
    mpc_or(tio, yield, F_nr, F_rs, F_ri);
    // F_nr = F_rs || F_ri
    ret_struct.F_r = F_nr;

    if(player0) {
      F_nr^=1;
    }
    // F_nr = !(F_rs || F_ri)
    run_coroutines(tio, [&tio, &ret_struct, F_nr, ptr](yield_t &yield)
        { mpc_select(tio, yield, ret_struct.ret_ptr, F_nr, ret_struct.ret_ptr, ptr);},
        [&tio, &bal_upd, F_rs, s1](yield_t &yield)
        { // If F_rs, we skipped a node, so update bal_upd to 1
          mpc_select(tio, yield, bal_upd, F_rs, bal_upd, s1);});
}

std::tuple<bool, RegBS> AVL::del(MPCTIO &tio, yield_t &yield, RegXS ptr, RegAS del_key,
      Duoram<Node>::Flat &A, RegBS found, RegBS find_successor, int TTL,
      avl_del_return &ret_struct) {
    bool player0 = tio.player()==0;
    if(TTL==0) {
        //Reconstruct and return found
        bool success = reconstruct_RegBS(tio, yield, found);
        RegBS zero;
        return {success, zero};
    } else {
        Node node;
        RegXS oldptrs;
        // This OblivIndex creation is not required if !AVL_OPT_ON, but for convenience we leave it in
        // so that fixImbalance has an oidx to be supplied when in the !AVL_OPT_ON setting.
        nbits_t width = ceil(log2(cur_max_index+1));
        typename Duoram<Node>::template OblivIndex<RegXS,1> oidx(tio, yield, ptr, width);
        #ifdef AVL_OPT_ON
            node = A[oidx];
            oldptrs = node.pointers;
        #else
            node = A[ptr];
        #endif

        RegXS left = getAVLLeftPtr(node.pointers);
        RegXS right = getAVLRightPtr(node.pointers);


        size_t &aes_ops = tio.aes_ops();
        RegBS l0, r0, lt, eq, gt;
        // Check if left and right children are 0
        // l0: Is left child 0
        // r0: Is right child 0
        run_coroutines(tio, [&tio, &l0, left, &aes_ops](yield_t &yield)
            { CDPF cdpf = tio.cdpf(yield);
              l0 = cdpf.is_zero(tio, yield, left, aes_ops);},
            [&tio, &r0, right, &aes_ops](yield_t &yield)
            { CDPF cdpf = tio.cdpf(yield);
              r0 = cdpf.is_zero(tio, yield, right, aes_ops);},
            // Compare key
            [&tio, &lt, &eq, &gt, del_key, node, aes_ops](yield_t &yield)
            { CDPF cdpf = tio.cdpf(yield);
              auto [a, b, c] = cdpf.compare(tio, yield, del_key - node.key, tio.aes_ops());
              lt = a; eq = b; gt = c;});

        // c is the direction bit for next_ptr
        // (c=0: go left or c=1: go right)
        RegBS c = gt;
        // lf = local found. We found the key to delete in this level.
        RegBS lf = eq;
        // F_{X}: Flags that indicate the number of children this node has
        // F_0: no children, F_1: one child, F_2: both children
        // F_n2: either F_0 or F_1
        RegBS F_0, F_1, F_2, F_n2;
        RegBS F_c1, F_c2, F_c3, F_c4, c_prime, F_dh, F_rs;
        RegXS next_ptr, cs_ptr;
        RegBS not_found = found;
        if(player0) {
            not_found^=1;
        }

        // F_1 = l0 \xor r0
        F_1 = l0 ^ r0;

        // F_0 = l0 & r0
        // Case 1: lf & F_1
        run_coroutines(tio, [&tio, &F_0, l0, r0](yield_t &yield)
            { mpc_and(tio, yield, F_0, l0, r0);},
            [&tio, &F_c1, lf, F_1](yield_t &yield)
            { mpc_and(tio, yield, F_c1, lf, F_1);},
            // Premptively computing flags for updateRetStruct in parallel
            // with above operations.
            [&tio, &F_dh, not_found, lf](yield_t &yield)
            { mpc_and(tio, yield, F_dh, not_found, lf);});

        // F_2 = !(F_0 ^ F_1) (Exactly 1 of F_0, F_1, and F_2 is true)
        F_n2 = F_0 ^ F_1;
        F_2 = F_n2;
        if(player0)
            F_2^=1;
        // s1: shares of 1 bit, s0: shares of 0 bit
        RegBS s1, s0;
        s1.set(tio.player()==1);

        // We set next ptr based on c, but we need to handle three
        // edge cases where we do not pick next_ptr by just the comparison result
        // Case 1: found the node here (lf), and node has only one child.
        // Then we iterate down the only child.
        // Set c_prime for Case 1
        run_coroutines(tio, [&tio, &c_prime, F_c1, c, l0](yield_t &yield)
            { mpc_select(tio, yield, c_prime, F_c1, c, l0);},
            [&tio, &F_c2, lf, F_2](yield_t &yield)
            { mpc_and(tio, yield, F_c2, lf, F_2);},
            // Premptively computing flags for updateRetStruct in parallel
            // with above operations.
            // If we have to i) delete here, and it doesn't have two children
            // we have to update child pointer in parent with the returned pointer
            [&tio, &F_rs, F_dh, F_n2](yield_t &yield)
            { mpc_and(tio, yield, F_rs, F_dh, F_n2);});

        // Case 2: found the node here (lf) and node has both children (F_2)
        // In find successor case, so we find inorder successor for node to be deleted
        // (inorder successor = go right and then find leftmost child.)

        // Case 3: finding successor (find_successor) and node has both children (F_2)
        // Go left.

        run_coroutines(tio, [&tio, &c_prime, F_c2, s1](yield_t &yield)
            { mpc_select(tio, yield, c_prime, F_c2, c_prime, s1);},
            [&tio, &F_c3, find_successor, F_2](yield_t &yield)
            { mpc_and(tio, yield, F_c3, find_successor, F_2);});

        // Case 4: finding successor (find_successor) and node has no more left children (l0)
        // This is the successor node then.
        // Go right (since no more left)
        run_coroutines(tio, [&tio, &c_prime, F_c3, s0](yield_t &yield)
            { mpc_select(tio, yield, c_prime, F_c3, c_prime, s0);},
            [&tio, &F_c4, find_successor, l0](yield_t &yield)
            { mpc_and(tio, yield, F_c4, find_successor, l0);},
            // Premptively computing flags for updateRetStruct in parallel
            // with above operations.
            [&tio, &ret_struct, F_c2](yield_t &yield)
            { mpc_or(tio, yield, ret_struct.F_ss, ret_struct.F_ss, F_c2);},
            [&tio, &ret_struct, F_dh, ptr](yield_t &yield)
            { mpc_select(tio, yield, ret_struct.N_d, F_dh, ret_struct.N_d, ptr);});

        RegBS found_prime, find_successor_prime;
        // F_sf = Flag for successor found.
        RegBS F_sf = F_c4;
        run_coroutines(tio, [&tio, &c_prime, F_c4, l0](yield_t &yield)
        { mpc_select(tio, yield, c_prime, F_c4, c_prime, l0);},
        [&tio, &F_rs, F_sf](yield_t &yield)
        { mpc_or(tio, yield, F_rs, F_rs, F_sf);},
        [&tio, &ret_struct, F_sf, ptr](yield_t &yield)
        { mpc_select(tio, yield, ret_struct.N_s, F_sf, ret_struct.N_s, ptr);});

        // Set next_ptr
        mpc_select(tio, yield, next_ptr, c_prime, left, right, AVL_PTR_SIZE);
        // cs_ptr: child's sibling pointer

        run_coroutines(tio, [&tio, &cs_ptr, c_prime, right, left](yield_t &yield)
            { mpc_select(tio, yield, cs_ptr, c_prime, right, left, AVL_PTR_SIZE);},
            [&tio, &found_prime, found, lf](yield_t &yield)
            { mpc_or(tio, yield, found_prime, found, lf);},
            // If in Case 2, set find_successor. We are now finding successor
            [&tio, &find_successor_prime, find_successor, F_c2](yield_t &yield)
            { mpc_or(tio, yield, find_successor_prime, find_successor, F_c2);});

        // If in Case 4. Successor found here already. Toggle find_successor off
        find_successor_prime=find_successor_prime^F_c4;

        TTL-=1;
        auto [key_found, bal_upd] = del(tio, yield, next_ptr, del_key, A, found_prime, find_successor_prime, TTL, ret_struct);

        // If we didn't find the key, we can end here.
        if(!key_found) {
          return {0, s0};
        }

        updateChildPointers(tio, yield, left, right, c_prime, ret_struct);
        setAVLLeftPtr(node.pointers, left);
        setAVLRightPtr(node.pointers, right);
        // Delay storing pointers back until balance updates are done as well.
        // Since we resolved the F_r flag returned with updateChildPointers(),
        // we set it back to 0.
        ret_struct.F_r = s0;

        RegBS p_bal_l, p_bal_r;
        p_bal_l = getLeftBal(node.pointers);
        p_bal_r = getRightBal(node.pointers);

        #ifdef AVL_DEBUG
          size_t rec_key = mpc_reconstruct(tio, yield, node.key, 64);
          bool rec_bal_upd = mpc_reconstruct(tio, yield, bal_upd);
          printf("current_key = %ld, bal_upd (before updateBalanceDel) = %d\n", rec_key, rec_bal_upd);
        #endif

        auto [new_p_bal_l, new_p_bal_r, new_bal_upd, imb] =
            updateBalanceDel(tio, yield, p_bal_l, p_bal_r, bal_upd, c_prime);
        bal_upd = new_bal_upd;

        #ifdef AVL_DEBUG
          bool rec_imb = mpc_reconstruct(tio, yield, imb);
          bool rec_new_bal_upd = mpc_reconstruct(tio, yield, new_bal_upd);
          printf("new_bal_upd (after updateBalanceDel) = %d, imb = %d\n", rec_new_bal_upd, rec_imb);
        #endif

        // F_ri: subflag for F_r. F_ri = returned flag set to 1 from imbalance fix.
        RegBS F_ri;
        fixImbalance(tio, yield, A, oidx, oldptrs, ptr, node.pointers, new_p_bal_l, new_p_bal_r, bal_upd,
              c_prime, cs_ptr, imb, F_ri, ret_struct);

        #ifdef AVL_DEBUG
          rec_imb = mpc_reconstruct(tio, yield, imb);
          rec_bal_upd = mpc_reconstruct(tio, yield, bal_upd);
          printf("imb (after fixImbalance) = %d, bal_upd = %d\n", rec_imb, rec_bal_upd);
        #endif
        updateRetStruct(tio, yield, ptr, F_rs, F_dh, F_ri, bal_upd, ret_struct);

        #ifdef AVL_DEBUG
          rec_bal_upd = mpc_reconstruct(tio, yield, bal_upd);
          printf("bal_upd (after updateRetStruct) = %d\n", rec_bal_upd);
        #endif

        return {key_found, bal_upd};
    }
}

/*
    The main AVL delete function.
    Trying to delete an item that does not exist in the tree will result in
    an explicit (non-oblivious) failure.
*/
bool AVL::del(MPCTIO &tio, yield_t &yield, RegAS del_key) {
    if(num_items==0)
        return 0;

    auto A = oram.flat(tio, yield, 0, cur_max_index+1);
    if(num_items==1) {
        //Delete root if root's key = del_key
        Node zero;
        nbits_t width = ceil(log2(cur_max_index+1));
        typename Duoram<Node>::template OblivIndex<RegXS,1> oidx(tio, yield, root, width);
        Node node = A[oidx];
        // Compare key
        CDPF cdpf = tio.cdpf(yield);
        auto [lt, eq, gt] = cdpf.compare(tio, yield, del_key - node.key, tio.aes_ops());
        bool success = reconstruct_RegBS(tio, yield, eq);
        if(success) {
            empty_locations.emplace_back(root);
            A[oidx] = zero;
            num_items--;
            return 1;
        } else {
            return 0;
        }
    } else {
        int TTL = AVL_TTL(num_items);
        // Flags for already found (found) item to delete and find successor (find_successor)
        // if this deletion requires a successor swap
        RegBS found, find_successor;
        avl_del_return ret_struct;
        auto [success, bal_upd] = del(tio, yield, root, del_key, A, found, find_successor, TTL, ret_struct);
        //printf ("Success =  %d\n", success);
        if(!success){
            return 0;
        }
        else{
            num_items--;

            /*
            printf("In delete's swap portion\n");
            Node rec_del_node = A.reconstruct(A[ret_struct.N_d]);
            Node rec_suc_node = A.reconstruct(A[ret_struct.N_s]);
            printf("del_node key = %ld, suc_node key = %ld\n",
                rec_del_node.key.ashare, rec_suc_node.key.ashare);
            printf("flag_s = %d\n", ret_struct.F_ss.bshare);
            */

            Node del_node, suc_node;
            nbits_t width = ceil(log2(cur_max_index+1));
            typename Duoram<Node>::template OblivIndex<RegXS,2> oidx_nd(tio, yield, ret_struct.N_d, width);
            typename Duoram<Node>::template OblivIndex<RegXS,2> oidx_ns(tio, yield, ret_struct.N_s, width);
            std::vector<coro_t> coroutines;
            #ifdef AVL_OPT_ON
                coroutines.emplace_back(
                    [&tio, &A, &oidx_nd, &del_node](yield_t &yield) {
                      auto acont = A.context(yield);
                      del_node = acont[oidx_nd];});
                coroutines.emplace_back(
                    [&tio, &A, &oidx_ns, &suc_node](yield_t &yield) {
                      auto acont = A.context(yield);
                      suc_node = acont[oidx_ns];});
                run_coroutines(tio, coroutines);
                coroutines.clear();
            #else
                del_node = A[ret_struct.N_d];
                suc_node = A[ret_struct.N_s];
            #endif
            RegAS zero_as; RegXS zero_xs;
            // Update root if needed
            mpc_select(tio, yield, root, ret_struct.F_r, root, ret_struct.ret_ptr);

            /*
            bool rec_F_ss = mpc_reconstruct(tio, yield, ret_struct.F_ss);
            size_t rec_del_key = mpc_reconstruct(tio, yield, del_node.key, 64);
            size_t rec_suc_key = mpc_reconstruct(tio, yield, suc_node.key, 64);
            printf("rec_F_ss = %d, del_node.key = %lu, suc_nod.key = %lu\n",
                rec_F_ss, rec_del_key, rec_suc_key);
            */
            RegXS old_del_value;
            RegAS old_del_key;
            #ifdef AVL_OPT_ON
                old_del_value = del_node.value;
                old_del_key = del_node.key;
            #endif
            RegXS empty_loc;

            run_coroutines(tio, [&tio, &del_node, ret_struct, suc_node](yield_t &yield)
                { mpc_select(tio, yield, del_node.key, ret_struct.F_ss, del_node.key, suc_node.key);},
                [&tio, &del_node, ret_struct, suc_node] (yield_t &yield)
                { mpc_select(tio, yield, del_node.value, ret_struct.F_ss, del_node.value, suc_node.value);},
                [&tio, &empty_loc, ret_struct](yield_t &yield)
                { mpc_select(tio, yield, empty_loc, ret_struct.F_ss, ret_struct.N_d, ret_struct.N_s);});

            #ifdef AVL_OPT_ON
                coroutines.emplace_back(
                    [&tio, &A, &oidx_nd, &del_node, old_del_key] (yield_t &yield) {
                        auto acont = A.context(yield);
                        acont[oidx_nd].NODE_KEY+=(del_node.key - old_del_key);
                    });
                coroutines.emplace_back(
                    [&tio, &A, &oidx_nd, &del_node, old_del_value] (yield_t &yield) {
                        auto acont = A.context(yield);
                        acont[oidx_nd].NODE_VALUE+=(del_node.value - old_del_value);
                    });
                coroutines.emplace_back(
                    [&tio, &A, &oidx_ns, &suc_node] (yield_t &yield) {
                        auto acont = A.context(yield);
                        acont[oidx_ns].NODE_KEY+=(-suc_node.key);
                    });
                coroutines.emplace_back(
                    [&tio, &A, &oidx_ns, &suc_node] (yield_t &yield) {
                        auto acont = A.context(yield);
                        acont[oidx_ns].NODE_VALUE+=(-suc_node.value);
                    });
                run_coroutines(tio, coroutines);
                coroutines.clear();
            #else
                A[ret_struct.N_d].NODE_KEY = del_node.key;
                A[ret_struct.N_d].NODE_VALUE = del_node.value;
                A[ret_struct.N_s].NODE_KEY = zero_as;
                A[ret_struct.N_s].NODE_VALUE = zero_xs;
            #endif

            //Add deleted (empty) location into the empty_locations vector for reuse in next insert()
            empty_locations.emplace_back(empty_loc);
        }

      return 1;
    }
}

/*

  Initializes a complete tree of size 2^depth

*/
void AVL::initialize(MPCTIO &tio, yield_t &yield, size_t depth) {
    size_t init_size = (size_t(1)<<depth) - 1;
    auto A = oram.flat(tio, yield);
    A.explicitonly(true);
    for(size_t i=1; i<=depth; i++) {
        size_t start = size_t(1)<<(i-1);
        size_t gap = size_t(1)<<i;
        size_t current = start;
        for(size_t j=1; j<=(size_t(1)<<(depth-i)); j++) {
            //printf("current = %ld ", current);
            Node node;
            node.key.set(current * tio.player());
            if(i!=1) {
                //Set left and right child pointers and balance bits
                size_t ptr_gap = start/2;
                RegXS lptr, rptr;
                lptr.set(tio.player() * (current-(ptr_gap)));
                rptr.set(tio.player() * (current+(ptr_gap)));
                setAVLLeftPtr(node.pointers, lptr);
                setAVLRightPtr(node.pointers, rptr);
            }
            A[current] = node;
            current+=gap;
        }
    }
    A.explicitonly(false);
    // Set num_items to init_size after they have been initialized;
    num_items = init_size;
    cur_max_index = num_items;
    // Set root correctly
    root.set(tio.player() * size_t(1)<<(depth-1));
}

// Now we use the AVL class in various ways.  This function is called by
// online.cpp.
void avl(MPCIO &mpcio,
    const PRACOptions &opts, char **args)
{
    int argc = 8;
    int depth = 0;          // Initialization depth
    size_t n_inserts = 0;   // Max ORAM_SIZE = 2^depth + n_inserts
    size_t n_deletes = 0;
    bool run_sanity = 0;

    // Process command line arguments
    for (int i = 0; i < argc; i += 2) {
        std::string option = args[i];
        if (option == "-m" && i + 1 < argc) {
            depth = std::atoi(args[i + 1]);
        } else if (option == "-i" && i + 1 < argc) {
            n_inserts = std::atoi(args[i + 1]);
        } else if (option == "-e" && i + 1 < argc) {
            n_deletes = std::atoi(args[i + 1]);
        } else if (option == "-s" && i + 1 < argc) {
            run_sanity = std::atoi(args[i + 1]);
        }
    }

    /* The ORAM will be initialized with 2^depth-1 items, but the 0 slot is reserved.
       So we initialize (initial inserts) with 2^depth-2 items.
       The ORAM size is set to 2^depth-1 + n_insert.
    */
    size_t init_size = (size_t(1)<<(depth));
    size_t oram_size = init_size + n_inserts;

    MPCTIO tio(mpcio, 0, opts.num_threads);
    run_coroutines(tio, [&tio, &mpcio, depth, oram_size, init_size, n_inserts, n_deletes, run_sanity] (yield_t &yield) {
        //printf("ORAM init_size = %ld, oram_size = %ld\n", init_size, oram_size);
        std::cout << "\n===== SETUP =====\n";
        AVL tree(tio.player(), oram_size);
        tree.initialize(tio, yield, depth);
        //tree.pretty_print(tio, yield);
        tio.sync_lamport();

        Node node;
        mpcio.dump_stats(std::cout);
        std::cout << "\n===== INSERTS =====\n";
        mpcio.reset_stats();
        tio.reset_lamport();

        for(size_t i = 1; i<=n_inserts; i++) {
            randomize_node(node);
            size_t ikey;
            #ifdef AVL_RANDOMIZE_INSERTS
                ikey = (1+(rand()%oram_size));
            #else
                ikey = (i+init_size);
            #endif
            printf("Insert key = %ld\n", ikey);
            node.key.set(ikey * tio.player());
            tree.insert(tio, yield, node);
            if(run_sanity) {
                tree.pretty_print(tio, yield);
                tree.check_avl(tio, yield);
            }
            //tree.print_oram(tio, yield);
        }

        tio.sync_lamport();
        mpcio.dump_stats(std::cout);
        std::cout << "\n===== DELETES =====\n";
        mpcio.reset_stats();
        tio.reset_lamport();
        for(size_t i = 1; i<=n_deletes; i++) {
            RegAS del_key;
            size_t dkey;
            #ifdef RANDOMIZE
                dkey = 1 + (rand()%init_size);
            #else
                dkey = i + 0;
            #endif
            del_key.set(dkey * tio.player());
            printf("Deletion key = %ld\n", dkey);
            tree.del(tio, yield, del_key);
            if(run_sanity) {
                tree.pretty_print(tio, yield);
                tree.check_avl(tio, yield);
            }
        }
    });
}


void avl_tests(MPCIO &mpcio,
    const PRACOptions &opts, char **args)
{
    // Not taking arguments for tests
    nbits_t depth=4;
    size_t items = (size_t(1)<<depth)-1;

    MPCTIO tio(mpcio, 0, opts.num_threads);
    run_coroutines(tio, [&tio, depth, items] (yield_t &yield) {
        size_t size = size_t(1)<<depth;
        bool player0 = tio.player()==0;
        AVL tree(tio.player(), size);

        // (T1) : Test 1 : L rotation (root modified)
        /*
            Operation:

              5                   7
               \                /   \
                7       --->   5     9
                 \
                  9

            T1 checks:
            - root is 7
            - 5,7,9 in correct positions
            - 5 and 9 have no children and 0 balances
        */
        {
            bool success = 1;
            int insert_array[] = {5, 7, 9};
            size_t insert_array_size = 2;
            Node node;

            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }
            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();

            Node root_node, left_node, right_node;
            size_t left_index, right_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            left_index = (getAVLLeftPtr(root_node.pointers)).share();
            right_index = (getAVLRightPtr(root_node.pointers)).share();
            left_node = R[left_index];
            right_node = R[right_index];

            if(left_node.key.share()!=5 || right_node.key.share()!=9) {
                success = false;
            }

            //To check that left and right have no children and 0 balances
            size_t sum = left_node.pointers.share() + right_node.pointers.share();
            if(sum!=0) {
                success = false;
            }
            if(player0) {
                if(success) {
                    print_green("T1 : SUCCESS\n");
                } else {
                    print_red("T1 : FAIL\n");
                }
            }
            /*
            //MY_tests:
            // OblivIndex read on the ORAM:
            RegXS mptr;
            mptr.set(tio.player() * 1);
            nbits_t width_bits = 2;
            typename Duoram<Node>::template OblivIndex<RegXS,1> oidx(tio, yield, mptr, width_bits);
            size_t rec_key = reconstruct_RegAS(tio, yield, A[oidx].NODE_KEY);
            printf("RI: Retrieved key (3) = %ld\n", rec_key);
            */
            A.init();
            tree.init();
        }

        // (T2) : Test 2 : L rotation (root unmodified)
        /*
            Operation:
                 5                        5
               /   \                    /   \
              3     7                  3     9
                     \     --->             /  \
                      9          7         7    12
                       \
                        12


            T2 checks:
            - root is 5
            - 3, 7, 9, 12 in expected positions
            - Nodes 3, 7, 12 have 0 balance and no children
            - 5's bal = 0 1

        */
        {
            bool success = 1;
            int insert_array[] = {5, 3, 7, 9, 12};
            size_t insert_array_size = 4;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n3, n7, n9, n12;
            size_t n3_index, n7_index, n9_index, n12_index;
            root_node = R[root];
            if((root_node.key).share()!=5) {
                success = false;
            }
            n3_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n3 = R[n3_index];
            n9 = R[n9_index];
            n7_index = getAVLLeftPtr(n9.pointers).share();
            n12_index = getAVLRightPtr(n9.pointers).share();
            n7 = R[n7_index];
            n12 = R[n12_index];

            // Node value checks
            if(n3.key.share()!=3 || n9.key.share()!=9) {
                success = false;
            }
            if(n7.key.share()!=7 || n12.key.share()!=12) {
                success = false;
            }

            // Node children and balance checks
            size_t zero = 0;
            zero+=(n3.pointers.share());
            zero+=(n7.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(getLeftBal(root_node.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getRightBal(root_node.pointers).share());
            if(one!=1) {
                success = false;
            }

            if(player0) {
                if(success) {
                    print_green("T2 : SUCCESS\n");
                } else {
                    print_red("T2 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T3) : Test 3 : R rotation (root modified)
        /*
            Operation:

                   9                 7
                  /                /   \
                 7         --->   5     9
                /
               5

            T3 checks:
            - root is 7
            - 5,7,9 in correct positions
            - 5 and 9 have no children

        */
        {
            bool success = 1;
            int insert_array[] = {9, 7, 5};
            size_t insert_array_size = 2;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();

            Node root_node, left_node, right_node;
            size_t left_index, right_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            left_index = (getAVLLeftPtr(root_node.pointers)).share();
            right_index = (getAVLRightPtr(root_node.pointers)).share();
            left_node = R[left_index];
            right_node = R[right_index];

            if(left_node.key.share()!=5 || right_node.key.share()!=9) {
                success = false;
            }

            //To check that left and right have no children and 0 balances
            size_t sum = left_node.pointers.share() + right_node.pointers.share();
            if(sum!=0) {
                success = false;
            }
            if(player0) {
                if(success) {
                    print_green("T3 : SUCCESS\n");
                } else{
                    print_red("T3 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T4) : Test 4 : R rotation (root unmodified)
        /*
            Operation:
                     9                        9
                   /   \                    /   \
                  7     12                 5     12
                 /              --->      / \
                5                    7   3   7
               /
              3


            T4 checks:
            - root is 9
            - 3,5,7,12 are in correct positions
            - Nodes 3,7,12 have 0 balance
            - Nodes 3,7,12 have no children
            - 9's bal = 1 0

        */
        {
            bool success = 1;
            int insert_array[] = {9, 12, 7, 5, 3};
            size_t insert_array_size = 4;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n3, n7, n5, n12;
            size_t n3_index, n7_index, n5_index, n12_index;
            root_node = R[root];
            if((root_node.key).share()!=9) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n12_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n12 = R[n12_index];
            n3_index = getAVLLeftPtr(n5.pointers).share();
            n7_index = getAVLRightPtr(n5.pointers).share();
            n7 = R[n7_index];
            n3 = R[n3_index];

            // Node value checks
            if(n12.key.share()!=12 || n5.key.share()!=5) {
                success = false;
            }
            if(n3.key.share()!=3 || n7.key.share()!=7) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n3.pointers.share());
            zero+=(n7.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getLeftBal(root_node.pointers).share());
            if(one!=1) {
                success = false;
            }
            if(player0) {
                if(success) {
                    print_green("T4 : SUCCESS\n");
                } else {
                    print_red("T4 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T5) : Test 5 : LR rotation (root modified)
        /*
            Operation:
                    9              9           7
                   /              /          /   \
                  5      -->     7     -->  5     9
                   \            /
                    7          5


            T5 checks:
            - root is 7
            - 9,5,7 are in correct positions
            - Nodes 5,7,9 have 0 balance
            - Nodes 5,9 have no children
        */

        {
            bool success = 1;
            int insert_array[] = {9, 5, 7};
            size_t insert_array_size = 2;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();

            Node root_node, n9, n5;
            size_t n9_index, n5_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n9 = R[n9_index];

            // Node value checks
            if(n9.key.share()!=9 || n5.key.share()!=5) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n5.pointers.share());
            zero+=(n9.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            if(zero!=0) {
                success = false;
            }
            if(player0) {
                if(success) {
                    print_green("T5 : SUCCESS\n");
                } else {
                    print_red("T5 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T6) : Test 6 : LR rotation (root unmodified)
        /*
            Operation:

                 9                      9                   9
               /   \                  /   \               /   \
              7     12               7     12            5     12
             /             --->     /           --->    / \
            3                      5                   3   7
             \                    /
              5                  3


            T6 checks:
            - root is 9
            - 3,5,7,12 are in correct positions
            - Nodes 3,7,12 have 0 balance
            - Nodes 3,7,12 have no children
            - 9's bal = 1 0

        */
        {
            bool success = 1;
            int insert_array[] = {9, 12, 7, 3, 5};
            size_t insert_array_size = 4;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n3, n7, n5, n12;
            size_t n3_index, n7_index, n5_index, n12_index;
            root_node = R[root];
            if((root_node.key).share()!=9) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n12_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n12 = R[n12_index];
            n3_index = getAVLLeftPtr(n5.pointers).share();
            n7_index = getAVLRightPtr(n5.pointers).share();
            n7 = R[n7_index];
            n3 = R[n3_index];

            // Node value checks
            if(n5.key.share()!=5 || n12.key.share()!=12) {
                success = false;
            }
            if(n3.key.share()!=3 || n7.key.share()!=7) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n3.pointers.share());
            zero+=(n7.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getLeftBal(root_node.pointers).share());
            if(one!=1) {
                success = false;
            }
            if(player0) {
                if(success) {
                    print_green("T6 : SUCCESS\n");
                } else {
                    print_red("T6 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T7) : Test 7 : RL rotation (root modified)
        /*
            Operation:
                5              5                7
                 \              \             /   \
                  9      -->     7      -->  5     9
                 /                \
                7                  9


            T7 checks:
            - root is 7
            - 9,5,7 are in correct positions
            - Nodes 5,7,9 have 0 balance
            - Nodes 5,9 have no children
        */

        {
            bool success = 1;
            int insert_array[] = {5, 9, 7};
            size_t insert_array_size = 2;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n9, n5;
            size_t n9_index, n5_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n9 = R[n9_index];

            // Node value checks
            if(n9.key.share()!=9 || n5.key.share()!=5) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n5.pointers.share());
            zero+=(n9.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            if(zero!=0) {
                success = false;
            }
            if(player0) {
                if(success) {
                    print_green("T7 : SUCCESS\n");
                } else {
                    print_red("T7 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }

        // (T8) : Test 8 : RL rotation (root unmodified)
        /*
            Operation:

                 5                     5                   5
               /   \                 /   \               /   \
              3     12              3     12            3     9
                   /      --->           /     --->          /  \
                  7                     9                   7    12
                   \                   /
                    9                 7


            T8 checks:
            - root is 5
            - 3,9,7,12 are in correct positions
            - Nodes 3,7,12 have 0 balance
            - Nodes 3,7,12 have no children
            - 5's bal = 0 1

        */
        {
            bool success = 1;
            int insert_array[] = {5, 3, 12, 7, 9};
            size_t insert_array_size = 4;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n3, n7, n9, n12;
            size_t n3_index, n7_index, n9_index, n12_index;
            root_node = R[root];
            if((root_node.key).share()!=5) {
                success = false;
            }
            n3_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n3 = R[n3_index];
            n9 = R[n9_index];
            n7_index = getAVLLeftPtr(n9.pointers).share();
            n12_index = getAVLRightPtr(n9.pointers).share();
            n7 = R[n7_index];
            n12 = R[n12_index];

            // Node value checks
            if(n3.key.share()!=3 || n9.key.share()!=9) {
                success = false;
            }
            if(n7.key.share()!=7 || n12.key.share()!=12) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n3.pointers.share());
            zero+=(n7.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(getLeftBal(root_node.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getRightBal(root_node.pointers).share());
            if(one!=1) {
                success = false;
            }
            if(player0) {
                if(success) {
                    print_green("T8 : SUCCESS\n");
                } else {
                    print_red("T8 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }

        // Deletion Tests:

        // (T9) : Test 9 : L rotation (root modified)
        /*
            Operation:

              5                    7
             / \       Del 3     /   \
            3   7     ------>   5     9
                 \
                  9

            T9 checks:
            - root is 7
            - 5,7,9 in correct positions
            - 5 and 9 have no children and 0 balances
            - 7 has 0 balances
        */
        {
            bool success = 1;
            int insert_array[] = {5, 3, 7, 9};
            size_t insert_array_size = 3;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(3 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);

            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();

            Node root_node, left_node, right_node;
            size_t left_index, right_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            left_index = (getAVLLeftPtr(root_node.pointers)).share();
            right_index = (getAVLRightPtr(root_node.pointers)).share();
            left_node = R[left_index];
            right_node = R[right_index];

            if(left_node.key.share()!=5 || right_node.key.share()!=9) {
                success = false;
            }

            //To check that left and right have no children and 0 balances
            size_t sum = left_node.pointers.share() + right_node.pointers.share();
            if(sum!=0) {
                success = false;
            }
            success &= del_ret;

            if(player0) {
                if(success) {
                    print_green("T9 : SUCCESS\n");
                } else {
                    print_red("T9 : FAIL\n");
                }
            }

            A.init();
            tree.init();
        }

        // (T10) : Test 10 : L rotation (root unmodified)
        /*
            Operation:
                 5                        5
               /   \                    /   \
              3     7      Del 6       3     9
             /     / \    ------>     /     /  \
            1     6   9              1     7    12
                       \
                        12


            T10 checks:
            - root is 5
            - 3, 7, 9, 12 in expected positions
            - Nodes 5, 7, 12 have 0 balance and no children
            - 3's bal = 1 0

        */
        {
            bool success = 1;
            int insert_array[] = {5, 3, 7, 9, 6, 1, 12};
            size_t insert_array_size = 6;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(6 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n1, n3, n7, n9, n12;
            size_t n1_index, n3_index, n7_index, n9_index, n12_index;
            root_node = R[root];
            if((root_node.key).share()!=5) {
                success = false;
            }
            n3_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n3 = R[n3_index];
            n9 = R[n9_index];
            n7_index = getAVLLeftPtr(n9.pointers).share();
            n12_index = getAVLRightPtr(n9.pointers).share();
            n7 = R[n7_index];
            n12 = R[n12_index];
            n1_index = getAVLLeftPtr(n3.pointers).share();
            n1 = R[n1_index];

            // Node value checks
            if(n3.key.share()!=3 || n9.key.share()!=9) {
                success = false;
            }
            if(n7.key.share()!=7 || n12.key.share()!=12 || n1.key.share()!=1) {
                success = false;
            }

            // Node children and balance checks
            size_t zero = 0;
            zero+=(n1.pointers.share());
            zero+=(n7.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(getLeftBal(root_node.pointers).share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            zero+=(getRightBal(n3.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getLeftBal(n3.pointers).share());
            if(one!=1) {
                success = false;
            }
            success &= del_ret;

            if(player0) {
                if(success) {
                    print_green("T10 : SUCCESS\n");
                } else {
                    print_red("T10 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }

        // (T11) : Test 11 : R rotation (root modified)
        /*
            Operation:

                   9                   7
                  / \     Del 12     /   \
                 7   12  ------->   5     9
                /
               5

            T11 checks:
            - root is 7
            - 5,7,9 in correct positions and balances to 0
            - 5 and 9 have no children

        */
        {
            bool success = 1;
            int insert_array[] = {9, 7, 12, 5};
            size_t insert_array_size = 3;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(12 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();

            Node root_node, left_node, right_node;
            size_t left_index, right_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            left_index = (getAVLLeftPtr(root_node.pointers)).share();
            right_index = (getAVLRightPtr(root_node.pointers)).share();
            left_node = R[left_index];
            right_node = R[right_index];

            if(left_node.key.share()!=5 || right_node.key.share()!=9) {
                success = false;
            }

            //To check that left and right have no children and 0 balances
            size_t zero = left_node.pointers.share() + right_node.pointers.share();
            zero+=(getLeftBal(left_node.pointers).share());
            zero+=(getRightBal(left_node.pointers).share());
            zero+=(getLeftBal(right_node.pointers).share());
            zero+=(getRightBal(right_node.pointers).share());
            if(zero!=0) {
                success = false;
            }
            success &= del_ret;

            if(player0) {
                if(success) {
                    print_green("T11 : SUCCESS\n");
                } else{
                    print_red("T11 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T12) : Test 12 : R rotation (root unmodified)
        /*
            Operation:
                     9                        9
                   /   \                    /   \
                  7     12      Del 8      5     12
                 / \     \     ------>    / \     \
                5   8     15             3   7     15
               /
              3


            T4 checks:
            - root is 9
            - 3,5,7,12,15 are in correct positions
            - Nodes 3,7,15 have 0 balance
            - Nodes 3,7,15 have no children
            - 9,5 bal = 0 0
            - 12 bal = 0 1
        */
        {
            bool success = 1;
            int insert_array[] = {9, 12, 7, 5, 8, 15, 3};
            size_t insert_array_size = 6;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(8 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n3, n7, n5, n12, n15;
            size_t n3_index, n7_index, n5_index, n12_index, n15_index;
            root_node = R[root];
            if((root_node.key).share()!=9) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n12_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n12 = R[n12_index];
            n3_index = getAVLLeftPtr(n5.pointers).share();
            n7_index = getAVLRightPtr(n5.pointers).share();
            n7 = R[n7_index];
            n3 = R[n3_index];
            n15_index = getAVLRightPtr(n12.pointers).share();
            n15 = R[n15_index];

            // Node value checks
            if(n12.key.share()!=12 || n5.key.share()!=5) {
                success = false;
            }
            if(n3.key.share()!=3 || n7.key.share()!=7 || n15.key.share()!=15) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n3.pointers.share());
            zero+=(n7.pointers.share());
            zero+=(n15.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getRightBal(n12.pointers).share());
            if(one!=1) {
                success = false;
            }
            success &= del_ret;

            if(player0) {
                if(success) {
                    print_green("T12 : SUCCESS\n");
                } else {
                    print_red("T12 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T13) : Test 13 : LR rotation (root modified)
        /*
            Operation:
                    9                   9           7
                   / \     Del 12      /          /   \
                  5   12  ------->    7     -->  5     9
                   \                 /
                    7               5


            T5 checks:
            - root is 7
            - 9,5,7 are in correct positions
            - Nodes 5,7,9 have 0 balance
            - Nodes 5,9 have no children
        */

        {
            bool success = 1;
            int insert_array[] = {9, 5, 12, 7};
            size_t insert_array_size = 3;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(12 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n9, n5;
            size_t n9_index, n5_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n9 = R[n9_index];

            // Node value checks
            if(n9.key.share()!=9 || n5.key.share()!=5) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n5.pointers.share());
            zero+=(n9.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            if(zero!=0) {
                success = false;
            }
            success &= del_ret;

            if(player0) {
                if(success) {
                    print_green("T13 : SUCCESS\n");
                } else {
                    print_red("T13 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T14) : Test 14 : LR rotation (root unmodified)
        /*
            Operation:

                 9                       9
               /   \                   /   \
              5     12     Del 8      5     12
             / \          ------>    / \
            3   7         (No-op)   3   7


            T6 checks:
            - root is 9
            - 3,5,7,12 are in correct positions
            - Nodes 3,7,12 have 0 balance
            - Nodes 3,7,12 have no children
            - 9's bal = 1 0

        */
        {
            bool success = 1;
            int insert_array[] = {9, 12, 7, 3, 5};
            size_t insert_array_size = 4;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(8 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n3, n7, n5, n12;
            size_t n3_index, n7_index, n5_index, n12_index;
            root_node = R[root];
            if((root_node.key).share()!=9) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n12_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n12 = R[n12_index];
            n3_index = getAVLLeftPtr(n5.pointers).share();
            n7_index = getAVLRightPtr(n5.pointers).share();
            n7 = R[n7_index];
            n3 = R[n3_index];

            // Node value checks
            if(n5.key.share()!=5 || n12.key.share()!=12) {
                success = false;
            }
            if(n3.key.share()!=3 || n7.key.share()!=7) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n3.pointers.share());
            zero+=(n7.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getLeftBal(root_node.pointers).share());
            if(one!=1) {
                success = false;
            }
            success &=(!del_ret);

            if(player0) {
                if(success) {
                    print_green("T14 : SUCCESS\n");
                } else {
                    print_red("T14 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }

        // (T15) : Test 15 : RL rotation (root modified)
        /*
            Operation:
                5              5                7
               / \     Del 3    \             /   \
              3   9   ------->   7      -->  5     9
                 /                \
                7                  9


            T15 checks:
            - root is 7
            - 9,5,7 are in correct positions
            - Nodes 5,7,9 have 0 balance
            - Nodes 5,9 have no children
        */

        {
            bool success = 1;
            int insert_array[] = {5, 9, 3, 7};
            size_t insert_array_size = 3;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(3 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n9, n5;
            size_t n9_index, n5_index;
            root_node = R[root];
            if((root_node.key).share()!=7) {
                success = false;
            }
            n5_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n5 = R[n5_index];
            n9 = R[n9_index];

            // Node value checks
            if(n9.key.share()!=9 || n5.key.share()!=5) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n5.pointers.share());
            zero+=(n9.pointers.share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n5.pointers).share());
            zero+=(getLeftBal(n5.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            if(zero!=0) {
                success = false;
            }
            success &= del_ret;

            if(player0) {
                if(success) {
                    print_green("T15 : SUCCESS\n");
                } else {
                    print_red("T15 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }

        // (T16) : Test 16 : RL rotation (root unmodified)
        /*
            Operation:

                 5                     5                   5
               /   \                 /   \               /   \
              3     8     Del 7     3     8             3     9
             /     /  \   ------>  /       \     --->  /     /  \
            1     7    12         1         9         1     8    12
                      /                      \
                     9                        12


            T8 checks:
            - root is 5
            - 3,9,8,12 are in correct positions
            - Nodes 1,5,8,9,12 have 0 balance
            - Nodes 1,5,8,9,12 have no children
            - Node 3 has 1 0 balance

        */
        {
            bool success = 1;
            int insert_array[] = {5, 3, 8, 7, 1, 12, 9};
            size_t insert_array_size = 6;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(7 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n1, n3, n8, n9, n12;
            size_t n1_index, n3_index, n8_index, n9_index, n12_index;
            root_node = R[root];
            if((root_node.key).share()!=5) {
                success = false;
            }
            n3_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n3 = R[n3_index];
            n9 = R[n9_index];
            n1_index = getAVLLeftPtr(n3.pointers).share();
            n8_index = getAVLLeftPtr(n9.pointers).share();
            n12_index = getAVLRightPtr(n9.pointers).share();
            n1 = R[n1_index];
            n8 = R[n8_index];
            n12 = R[n12_index];

            // Node value checks
            if(n1.key.share()!=1) {
                success = false;
            }
            if(n3.key.share()!=3 || n9.key.share()!=9) {
                success = false;
            }
            if(n8.key.share()!=8 || n12.key.share()!=12) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n1.pointers.share());
            zero+=(getRightBal(n3.pointers).share());
            zero+=(n8.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(getLeftBal(root_node.pointers).share());
            zero+=(getRightBal(root_node.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            if(zero!=0) {
                success = false;
            }
            success &= del_ret;

            if(player0) {
                if(success) {
                    print_green("T16 : SUCCESS\n");
                } else {
                    print_red("T16 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }


        // (T17) : Test 17 : Double imbalance (root modified)
        /*
            Operation:

                      9                                     9
                   /     \                               /     \
                  5        12        Del 10             5        15
                /   \     /  \      -------->        /    \      /  \
               3     7   10   15                    3      7    12   20
              / \   / \        \                   / \    / \
             2   4 6   8        20                2   4  6   8
            /                                    /
           1                                    1


                                5
                             /     \
                           3          9
            ----->        / \       /   \
                         2   4     7      15
                        /         / \    /   \
                       1         6   8  10    20




            T17 checks:
            - root is 5
            - all other nodes are in correct positions
            - balances and children are correct
        */
        {
            bool success = 1;
            int insert_array[] = {9, 5, 12, 7, 3, 10, 15, 2, 4, 6, 8, 20, 1};
            size_t insert_array_size = 12;
            Node node;
            for(size_t i = 0; i<=insert_array_size; i++) {
              randomize_node(node);
              node.key.set(insert_array[i] * tio.player());
              tree.insert(tio, yield, node);
              tree.check_avl(tio, yield);
            }

            RegAS del_key;
            del_key.set(10 * tio.player());
            bool del_ret;
            del_ret = tree.del(tio, yield, del_key);
            tree.check_avl(tio, yield);

            Duoram<Node>* oram = tree.get_oram();
            RegXS root_xs = tree.get_root();
            size_t root = mpc_reconstruct(tio, yield, root_xs);
            auto A = oram->flat(tio, yield);
            auto R = A.reconstruct();
            Node root_node, n3, n7, n9;
            Node n1, n2, n4, n6, n8, n12, n15, n20;
            size_t n3_index, n7_index, n9_index;
            size_t n1_index, n2_index, n4_index, n6_index;
            size_t n8_index, n12_index, n15_index, n20_index;
            root_node = R[root];
            if((root_node.key).share()!=5) {
                success = false;
            }
            n3_index = (getAVLLeftPtr(root_node.pointers)).share();
            n9_index = (getAVLRightPtr(root_node.pointers)).share();
            n3 = R[n3_index];
            n9 = R[n9_index];

            n2_index = getAVLLeftPtr(n3.pointers).share();
            n4_index = getAVLRightPtr(n3.pointers).share();
            n7_index = getAVLLeftPtr(n9.pointers).share();
            n15_index = getAVLRightPtr(n9.pointers).share();
            n2 = R[n2_index];
            n4 = R[n4_index];
            n7 = R[n7_index];
            n15 = R[n15_index];

            n1_index = getAVLLeftPtr(n2.pointers).share();
            n6_index = getAVLLeftPtr(n7.pointers).share();
            n8_index = getAVLRightPtr(n7.pointers).share();
            n12_index = getAVLLeftPtr(n15.pointers).share();
            n20_index = getAVLRightPtr(n15.pointers).share();
            n1 = R[n1_index];
            n6 = R[n6_index];
            n8 = R[n8_index];
            n12 = R[n12_index];
            n20 = R[n20_index];

            // Node value checks
            if(n3.key.share()!=3 || n9.key.share()!=9) {
                success = false;
            }
            if(n2.key.share()!=2 || n4.key.share()!=4) {
                success = false;
            }
            if(n7.key.share()!=7 || n15.key.share()!=15) {
                success = false;
            }
            if(n1.key.share()!=1 || n6.key.share()!=6 || n8.key.share()!=8) {
                success = false;
            }
            if(n12.key.share()!=12 || n20.key.share()!=20) {
                success = false;
            }

            // Node balance checks
            size_t zero = 0;
            zero+=(n1.pointers.share());
            zero+=(n4.pointers.share());
            zero+=(n6.pointers.share());
            zero+=(n8.pointers.share());
            zero+=(n12.pointers.share());
            zero+=(n20.pointers.share());
            zero+=(getLeftBal(n7.pointers).share());
            zero+=(getRightBal(n7.pointers).share());
            zero+=(getLeftBal(n9.pointers).share());
            zero+=(getRightBal(n9.pointers).share());
            zero+=(getLeftBal(n15.pointers).share());
            zero+=(getRightBal(n15.pointers).share());
            zero+=(getRightBal(n3.pointers).share());
            zero+=(getLeftBal(root_node.pointers).share());
            zero+=(getRightBal(root_node.pointers).share());
            if(zero!=0) {
                success = false;
            }
            int one = (getLeftBal(n3.pointers).share());
            if(one!=1) {
                success = false;
            }
            success &= del_ret;
            if(player0) {
                if(success) {
                    print_green("T17 : SUCCESS\n");
                } else {
                    print_red("T17 : FAIL\n");
                }
            }
            A.init();
            tree.init();
        }

    });
}