update 46.全排列 JavaScript版本

problems/0046.全排列.md

@@ -244,31 +244,35 @@ func backtrack(nums,pathNums []int,used []bool){
     }
 }
 
+```
+
 Javascript:
 
-```javascript
+```js
 
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
 var permute = function(nums) {
-    let result = []
-    let path = []
-    function backtracing(used) {
-        if(path.length === nums.length) {
-            result.push(path.slice(0))
-            return
+    const res = [], path = [];
+    backtracking(nums, nums.length, []);
+    return res;
+    
+    function backtracking(n, k, used) {
+        if(path.length === k) {
+            res.push(Array.from(path));
+            return;
         }
-        for(let i = 0; i < nums.length; i++) {
-            if(used[nums[i]]) {
-                continue
-            }
-            used[nums[i]] = true
-            path.push(nums[i])
-            backtracing(used)
-            path.pop()
-            used[nums[i]] = false
+        for (let i = 0; i < k; i++ ) {
+            if(used[i]) continue;
+            path.push(n[i]);
+            used[i] = true; // 同支
+            backtracking(n, k, used);
+            path.pop();
+            used[i] = false;
         }
     }
-    backtracing([])
-    return result
 };
 
 ```