添加40.组合总和IIJavaScript版本

problems/0040.组合总和II.md

@@ -293,7 +293,7 @@ class Solution {
 }
 ```
 Python：
-```python3
+```py
 class Solution:
     def combinationSum2(self, candidates: List[int], target: int) -> List[List[int]]:
         res = []
@@ -314,7 +314,39 @@ class Solution:
 ```
 Go：
 
+javaScript： 
 
+```js
+/**
+ * @param {number[]} candidates
+ * @param {number} target
+ * @return {number[][]}
+ */
+var combinationSum2 = function(candidates, target) {
+    const res = []; path = [], len = candidates.length;
+    candidates.sort();
+    backtracking(0, 0);
+    return res;
+    function backtracking(sum, i) {
+        if (sum > target) return;
+        if (sum === target) {
+            res.push(Array.from(path));
+            return;
+        }
+        let f = -1;
+        for(let j = i; j < len; j++) {
+            const n = candidates[j];
+            if(n > target - sum || n === f) continue;
+            path.push(n);
+            sum += n;
+            f = n;
+            backtracking(sum, j + 1);
+            path.pop();
+            sum -= n;
+        }
+    }
+};
+```
 
 
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