Merge pull request #1143 from Aaron-Lin-74/patch-3

Update 0024.两两交换链表中的节点.md

problems/0024.两两交换链表中的节点.md

@@ -254,32 +254,20 @@ TypeScript：
 
 ```typescript
 function swapPairs(head: ListNode | null): ListNode | null {
-    /**
+  const dummyHead: ListNode = new ListNode(0, head);
-     * 初始状态：
+  let cur: ListNode = dummyHead;
-     * curNode -> node1 -> node2 -> tmepNode
+  while(cur.next !== null && cur.next.next !== null) {
-     * 转换过程：
+    const tem: ListNode = cur.next;
-     * curNode -> node2
+    const tem1: ListNode = cur.next.next.next;
-     * curNode -> node2 -> node1
-     * curNode -> node2 -> node1 -> tempNode
-     * curNode = node1
-     */
-    let retNode: ListNode | null = new ListNode(0, head),
-        curNode: ListNode | null = retNode,
-        node1: ListNode | null = null,
-        node2: ListNode | null = null,
-        tempNode: ListNode | null = null;
     
-    while (curNode && curNode.next && curNode.next.next) {
+    cur.next = cur.next.next; // step 1
-        node1 = curNode.next;
+    cur.next.next = tem; // step 2
-        node2 = curNode.next.next;
+    cur.next.next.next = tem1; // step 3
-        tempNode = node2.next;
+    
-        curNode.next = node2;
+    cur = cur.next.next;
-        node2.next = node1;
+  }
-        node1.next = tempNode;
+  return dummyHead.next;
-        curNode = node1;
 }
-    return retNode.next;
-};
 ```
 
 Kotlin: