添加（0019.删除链表的倒数第N个节点.md）：增加typescript版本

problems/0019.删除链表的倒数第N个节点.md

@@ -181,7 +181,27 @@ var removeNthFromEnd = function(head, n) {
     return ret.next;
 };
 ```
+TypeScript:
+
+```typescript
+function removeNthFromEnd(head: ListNode | null, n: number): ListNode | null {
+    let newHead: ListNode | null = new ListNode(0, head);
+    let slowNode: ListNode | null = newHead,
+        fastNode: ListNode | null = newHead;
+    for (let i = 0; i < n; i++) {
+        fastNode = fastNode.next;
+    }
+    while (fastNode.next) {
+        fastNode = fastNode.next;
+        slowNode = slowNode.next;
+    }
+    slowNode.next = slowNode.next.next;
+    return newHead.next;
+};
+```
+
 Kotlin:
+
 ```Kotlin
 fun removeNthFromEnd(head: ListNode?, n: Int): ListNode? {
     val pre = ListNode(0).apply {