目录

LeetCode-206题

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LeetCode-206题

给定一个单链表的头节点，请反转链表，并返回反转后的链表

class Solution {public ListNode reverseList(ListNode head) {// checkif (head == null || head.next == null)return head;// 双指针ListNode p1 = head;ListNode p2 = head.next;// 一直到p2指向nullwhile (p2 != null) {ListNode curr = p1;p1 = p2;if (curr == head) {curr.next = null;}// 定义一个临时变量存放此时p2的下一个节点ListNode tmp = p2.next;p2.next = curr;p2 = tmp;}return p1;}private static class ListNode {int val;ListNode next;public ListNode() {}public ListNode(int val) {this.val = val;}public ListNode(int val, ListNode next) {this.val = val;this.next = next;}}
}