Merge pull request youngyangyang04#1195 from xiaofei-2020/back16

添加（0047.全排列II.md）：增加typescript版本

Author: youngyangyang04

problems/0047.全排列II.md

@@ -292,6 +292,34 @@ var permuteUnique = function (nums) {
 
 ```
 
+### TypeScript
+
+```typescript
+function permuteUnique(nums: number[]): number[][] {
+    nums.sort((a, b) => a - b);
+    const resArr: number[][] = [];
+    const usedArr: boolean[] = new Array(nums.length).fill(false);
+    backTracking(nums, []);
+    return resArr;
+    function backTracking(nums: number[], route: number[]): void {
+        if (route.length === nums.length) {
+            resArr.push(route.slice());
+            return;
+        }
+        for (let i = 0, length = nums.length; i < length; i++) {
+            if (i > 0 && nums[i] === nums[i - 1] && usedArr[i - 1] === false) continue;
+            if (usedArr[i] === false) {
+                route.push(nums[i]);
+                usedArr[i] = true;
+                backTracking(nums, route);
+                usedArr[i] = false;
+                route.pop();
+            }
+        }
+    }
+};
+```
+
 ### Swift
 
 ```swift