题目介绍

题解

class Solution {public void reorderList(ListNode head) {ListNode mid = middleNode(head);ListNode head2 = reverseList(mid);while (head2.next != null) {ListNode nxt = head.next;ListNode nxt2 = head2.next;head.next = head2;head2.next = nxt;head = nxt;head2 = nxt2;}}// 876. 链表的中间结点private ListNode middleNode(ListNode head) {ListNode slow = head, fast = head;while (fast != null && fast.next != null) {slow = slow.next;fast = fast.next.next;}return slow;}// 206. 反转链表private ListNode reverseList(ListNode head) {ListNode pre = null, cur = head;while (cur != null) {ListNode nxt = cur.next;cur.next = pre;pre = cur;cur = nxt;}return pre;}
}