白菜刷LeetCode记-46. Permutations

 1 /**
 2  * @param {number[]} nums
 3  * @return {number[][]}
 4  */
 5 var permute = function(nums) {
 6     var res = new Array();
 7     
 8     helper(nums, 0, nums.length - 1 , res);
 9     
10     return res;
11 };
12 
13 var helper = function(nums, k, n, res){
14     
15     if(k==n){
16         let tmparr = new Array();
17         nums.forEach(function(v,i){
18             tmparr.push(v);
19         });
20         res.push(tmparr);
21     }else{
22         for(let i = k ; i <= n ; i++){
23             let tmp = nums[k];
24             nums[k] = nums[i];
25             nums[i] = tmp;
26             
27             helper(nums, k+1, n, res);
28             
29             tmp = nums[k];
30             nums[k] = nums[i];
31             nums[i] = tmp;
32         }
33     }
34 }