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);

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 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 permutation(string &s) {
    permu_helper(s, 0);
}


void permu_helper(string &s, int level) {
    if (level == s.size()) {
        cout << s << endl;
        return;
    }

Onaiplee

void reverse(stack<int> &st) {
    if (!st.empty()) {
        int temp = st.top();
        st.pop();
        reverse(st);
        insert_botom(st, temp);
    }
}

Onaiplee

void print_external_nodes(shared_ptr<BinaryTree> root) {
  if (!root) {
    return;
  }
  left_dfs(root->left, true);
  right_dfs(root->right, true);
  
}

void left_dfs(shared_ptr<BinaryTree> n, bool is_ext) {

Onaiplee

class Solution {
public:
    vector<string> letterCombinations(string digits) {
        vector<string> mmap({"abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"});
        string buf;
        vector<string> result;
        dfs(0, mmap, buf, digits, result);
        return result;
    }
    

Onaiplee

class Solution {
public:
    int minCut(string s) {
        vector<vector<int>> p_map;
        vector<int> c_map;
        for (int i = 0; i < s.size(); i++) {
            p_map.push_back(vector<int>(s.size(), -1));
            c_map.push_back(-1);
        }
        for (int i = 0; i < s.size(); i++) {

Onaiplee

class Solution {
public:
    int numDistinct(string S, string T) {
        return numDistinct(S, T, 0, 0);
    }
    
    int numDistinct(string S, string T, int s, int t) {
        if (t == T.size()) {
            return 1;
        }

Onaiplee

class Solution {
public:
    int numDistinct(string S, string T) {
        int **mmap = (int **) malloc((S.size() + 1) * sizeof(int *));
        for (int i = 0; i < S.size() + 1; ++i) {
            mmap[i] = (int *) malloc((T.size() + 1) * sizeof(int));
        }
        for (int i = 0; i < S.size() + 1; ++i) {
            mmap[i][0] = 1;
        }