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 next = null, pre = null;
       while(head != null){
        next = head.next;
        head.next = pre;
        pre = head;
        head = next;
       }
        return pre;
    }
}