[LeetCode]206. Reverse Linked List

Reverse a singly linked list.

思路：新建链表，将原来链表元素一次取出放在新链表的头部的后面，返回新链表头.next

</pre><pre name="code" class="java">/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode reverseList(ListNode head) {
        if (head == null || head.next == null) return head;
        ListNode p = head;
        ListNode res = new ListNode(0);
        ListNode restemp = null;
        while (p != null) {
            restemp = res.next;
            res.next = p;
            p = p.next;
            res.next.next = restemp;
        }
        return res.next;
    }
}