Merge pull request #1181 from xiaofei-2020/back08

添加（0040.组合总和II.md）：增加typescript版本

problems/0040.组合总和II.md

@@ -532,6 +532,7 @@ var combinationSum2 = function(candidates, target) {
 };
 ```
 **使用used去重**
+
 ```js
 var combinationSum2 = function(candidates, target) {
     let res = [];
@@ -562,6 +563,37 @@ var combinationSum2 = function(candidates, target) {
 };
 ```
 
+## TypeScript
+
+```typescript
+function combinationSum2(candidates: number[], target: number): number[][] {
+    candidates.sort((a, b) => a - b);
+    const resArr: number[][] = [];
+    function backTracking(
+        candidates: number[], target: number,
+        curSum: number, startIndex: number, route: number[]
+    ) {
+        if (curSum > target) return;
+        if (curSum === target) {
+            resArr.push(route.slice());
+            return;
+        }
+        for (let i = startIndex, length = candidates.length; i < length; i++) {
+            if (i > startIndex && candidates[i] === candidates[i - 1]) {
+                continue;
+            }
+            let tempVal: number = candidates[i];
+            route.push(tempVal);
+            backTracking(candidates, target, curSum + tempVal, i + 1, route);
+            route.pop();
+
+        }
+    }
+    backTracking(candidates, target, 0, 0, []);
+    return resArr;
+};
+```
+
 ## C 
 
 ```c