Merge pull request #1037 from xiaofei-2020/str5

添加（剑指Offer58-II.左旋转字符串.md）：增加TypeScript和JavaScript版本

problems/剑指Offer58-II.左旋转字符串.md

@@ -209,6 +209,61 @@ var reverseLeftWords = function(s, n) {
 };
 ```
 
+版本二（在原字符串上操作）：
+
+```js
+/**
+ * @param {string} s
+ * @param {number} n
+ * @return {string}
+ */
+var reverseLeftWords = function (s, n) {
+    /** Utils */
+    function reverseWords(strArr, start, end) {
+        let temp;
+        while (start < end) {
+            temp = strArr[start];
+            strArr[start] = strArr[end];
+            strArr[end] = temp;
+            start++;
+            end--;
+        }
+    }
+    /** Main code */
+    let strArr = s.split('');
+    let length = strArr.length;
+    reverseWords(strArr, 0, length - 1);
+    reverseWords(strArr, 0, length - n - 1);
+    reverseWords(strArr, length - n, length - 1);
+    return strArr.join('');
+};
+```
+
+TypeScript：
+
+```typescript
+function reverseLeftWords(s: string, n: number): string {
+    /** Utils */
+    function reverseWords(strArr: string[], start: number, end: number): void {
+        let temp: string;
+        while (start < end) {
+            temp = strArr[start];
+            strArr[start] = strArr[end];
+            strArr[end] = temp;
+            start++;
+            end--;
+        }
+    }
+    /** Main code */
+    let strArr: string[] = s.split('');
+    let length: number = strArr.length;
+    reverseWords(strArr, 0, length - 1);
+    reverseWords(strArr, 0, length - n - 1);
+    reverseWords(strArr, length - n, length - 1);
+    return strArr.join('');
+};
+```
+
 Swift:
 
 ```swift