LeetCode:46.全排列

LeetCode:46.全排列

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function (nums) {
  let res = [];
  let compose = (path) => {
    if (path.length === nums.length) {
      res.push(path);
      return;
    }
    for (let i = 0; i < nums.length; i++) {
      if (!path.includes(nums[i])) {
        compose(path.concat(nums[i]));
      }
    }
  };
  compose([]);
  return res;
};
let nums = [1, 2, 3];
console.log(permute(nums));

解题步骤用递归模拟出所有情况。遇到包含重复元素的情况，就回溯。收集所有到达递归终点的情况，并返回。

时间复杂度：O（n！)，n！=1×2×3×..×（n-1)×n空间复杂度：O(n)

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