Merge pull request #1180 from xiaofei-2020/back07

添加（0039.组合总和.md）：增加typescript版本

problems/0039.组合总和.md

@@ -392,7 +392,34 @@ var combinationSum = function(candidates, target) {
 };
 ```
 
+## TypeScript
+
+```typescript
+function combinationSum(candidates: number[], target: number): number[][] {
+    const resArr: number[][] = [];
+    function backTracking(
+        candidates: number[], target: number,
+        startIndex: number, route: number[], curSum: number
+    ): void {
+        if (curSum > target) return;
+        if (curSum === target) {
+            resArr.push(route.slice());
+            return
+        }
+        for (let i = startIndex, length = candidates.length; i < length; i++) {
+            let tempVal: number = candidates[i];
+            route.push(tempVal);
+            backTracking(candidates, target, i, route, curSum + tempVal);
+            route.pop();
+        }
+    }
+    backTracking(candidates, target, 0, [], 0);
+    return resArr;
+};
+```
+
 ## C 
+
 ```c
 int* path;
 int pathTop;