文章目录
- 题目介绍
- 题解
题目介绍
题解
利用25题K个一组反转链表链接 ,将k改为2即可。
// 同 25题 K个一组反转链表
class Solution {public ListNode swapPairs(ListNode head) {// 统计节点个数int n = 0;for (ListNode cur = head; cur != null; cur = cur.next) {n++;}ListNode dummy = new ListNode(0, head);ListNode p0 = dummy;ListNode pre = null;ListNode cur = head;// 2 个一组处理for (; n >= 2; n -= 2) {for (int i = 0; i < 2; i++) { ListNode nxt = cur.next;cur.next = pre; pre = cur;cur = nxt;}ListNode nxt = p0.next;p0.next.next = cur;p0.next = pre;p0 = nxt;}return dummy.next;}
}