【链表】- 两两交换链表中的节点

1. 对应力扣题目连接

• 两两交换链表中的节点

2. 实现案例代码

public class ExchangeLinkedListsPairwise {public static void main(String[] args) {// 示例链表：[1, 2, 3, 4]ListNode head = new ListNode(1);head.next = new ListNode(2);head.next.next = new ListNode(3);head.next.next.next = new ListNode(4);// 迭代方法ListNode swapPairsIterative = swapPairsIterative(head);printList(swapPairsIterative); // 输出：[2, 1, 4, 3]}// 迭代方法实现public static ListNode swapPairsIterative(ListNode head) {// 创建一个虚拟头节点ListNode dummy = new ListNode(0);dummy.next = head;ListNode prev = dummy;while (head != null && head.next != null) {ListNode firstNode = head;ListNode secondNode = head.next;// 交换节点prev.next = secondNode;firstNode.next = secondNode.next;secondNode.next = firstNode;// 更新指针prev = firstNode;head = firstNode.next; // 移动到下一个未交换的节点}return dummy.next;}public static void printList(ListNode head) {ListNode current = head;while (current != null) {System.out.print(current.val + " ");current = current.next;}System.out.println();}}class ListNode {public int val;public ListNode next;ListNode() {}ListNode(int val) {this.val = val;}ListNode(int val, ListNode next) {this.val = val;this.next = next;}
}