Onaiplee

void encode_word(string &s) {
    encode_word_helper(s, 0);
}

void encode_word_helper(string &s, int i) {
    if (i == s.size()) {
        cout << reduce(s) << endl;
        return;
    }
    

Onaiplee

void mutate_tree_bfs(const shared_ptr<BinaryTree> &root) {
    stack<shared_ptr<BinaryTree>> stack1;
    stack<shared_ptr<BinaryTree>> stack2;
    
    stack<shared_ptr<BinaryTree>> *st1 = &stack1;
    stack<shared_ptr<BinaryTree>> &st2 = &stack2;
    
    st1->push(root);
    shared_ptr<BinaryTree> *temp = nullptr;
    bool is_left_most = true;

Onaiplee

void mutate_binary_tree(const shared_ptr<BinaryTree> &root) {
    if (!root) {
        return;
    }
    mute_dfs_post_order(root);
    shared_ptr<BinaryTree> n = root;
    while (n->left) {
        auto current = n;
        auto next = current->left;
        next = get_right_most(next);