Problem
Given a collection of distinct integers, return all possible permutations.
Example:
Input: [1,2,3] Output: [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ] Solution
/** * @param {number[]} nums * @return {number[][]} */ var permute = function(nums) { var res = []; dfs(res, [], nums); return res; }; var dfs = function (res, arr, nums) { var len = nums.length; var tmp1 = null; var tmp2 = null; if (!len) return res.push(arr); for (var i = 0; i < len; i++) { tmp1 = Array.from(arr); tmp1.push(nums[i]); tmp2 = Array.from(nums); tmp2.splice(i, 1); dfs(res, tmp1, tmp2); } }; Explain:
nope.
Complexity:
- Time complexity : O(n!).
- Space complexity :