46.全排列 ​

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function (nums) {
  const res = [];
  function fn(path, used) {
    if (path.length === nums.length) {
      res.push([...path]);
      return;
    }
    for (let i = 0; i < nums.length; i++) {
      if (used[i]) continue;
      used[i] = true;
      fn(path.concat(nums[i]), used);
      used[i] = false;
    }
  }
  fn([], []);
  return res;
};

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function (nums) {
  const res = [];
  function fn(path, used) {
    if (path.length === nums.length) {
      res.push([...path]);
      return;
    }
    for (let i = 0; i < nums.length; i++) {
      if (used[i]) continue;
      used[i] = true;
      fn(path.concat(nums[i]), used);
      used[i] = false;
    }
  }
  fn([], []);
  return res;
};