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title: 反转链表 date: 2019-08-21T11:00:41+08:00 draft: false categories: offer

题目

牛客网

输入一个链表，反转链表后，输出新链表的表头。

解题思路

1. 三个指针

public ListNode ReverseList(ListNode head) {
    if (head == null || head.next == null) {
        return head;
    }

    ListNode pre = head, cur = head.next, next;
    pre.next = null;

    while (cur != null) {
        next = cur.next;
        cur.next = pre;

        pre = cur;
        cur = next;
    }

    return pre;
}