题解 | #反转链表#

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode ReverseList(ListNode head) {
        ListNode pre = null;
        ListNode p = null;
        while(head != null) {
            p = head.next;

            head.next = pre;

            pre = head;

            head = p;
        }
        return pre;
    }
}