[LeetCode] Reverse Linked List

Problem:

Reverse a singly linked list.

Java Code:(难得做出个一次AC的)

/**
 * 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) {
        ListNode pre = null;
        ListNode p = head;
        
        while (p != null) {
            ListNode tmp = p.next;
            p.next = pre;
            pre = p;
            p = tmp;
        }
        
        return pre;
    }
}