youngdo212

function quickSort(arr){
  if(arr.length === 0) return arr;

  let pivot = arr.pop();
  let i = -1;
  for(j = 0; j < arr.length; j++){
    if(arr[j] <= pivot){
      i++;
      [arr[i], arr[j]] = [arr[j], arr[i]];
    }

youngdo212

function fibonacci(n, memo = {0: 0, 1: 1}){
  if(memo[n] !== undefined)  return memo[n];

  memo[n] = fibonacci(n-1, memo) + fibonacci(n-2, memo);

  return memo[n];
}

youngdo212

function solution(n, arr1, arr2){
  let result = [];

  for(i = 0; i < n; i ++){
    let row = (arr1[i] | arr2[i]).toString(2);
    row = row.replace(/1/g, '#');
    row = row.replace(/0/g, ' ');
    result.push(row)
  }

youngdo212

function solution(n) {
    let result = [];

    result = result.concat(move(n, 1, 3));

    return result
}

function move(depth, source, target){
    if(depth === 1) return [[source, target]];

youngdo212

function solution(s){
  let {length} = s;
  while(length){
      for(let i = 0; i + length <= s.length; i++){
          if(isPalin(s.slice(i,i+length))) return length;
      }
      length--
  }
}

youngdo212

function solution(n) {
    let result = 0;
    
    for(let i = 1; i <= n; i++){
        let temp = 0;
        
        for(let j = i; temp < n; j++){
            temp += j;
        }
        

youngdo212

function solution(n) {
    var answer = '';
    
    while(n > 0){
        const remainder = n%3 || 3;
        answer = (remainder === 3 ? 4 : remainder) + answer;
        n = (n-remainder)/3;
    }
    
    return answer;

youngdo212

var invertTree = function(root) {
    if(root === null) return null;
    const [invertedLeft, invertedRight] = [invertTree(root.left), invertTree(root.right)];
    ([root.left, root.right] = [invertedRight, invertedLeft]);
    return root;
};

youngdo212

var singleNumber = function(nums) {
    return nums.reduce((acc,cur) => acc^cur);
};

youngdo212

function mergeTrees(t1, t2){
  if(t1 === null || t2 === null) return t1 ? t1 : t2 ? t2 : null;
  let newTree = new TreeNode(t1.val+t2.val);
  newTree.left = mergeTrees(t1.left, t2.left);
  newTree.right = mergeTrees(t1.right, t2.right);
  return newTree;
}