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) {
        if(head==null||head.next==null)
            return head;
        
        ListNode pre = null;        
        ListNode cur = head;
        while(cur!=null){
            ListNode next = cur.next;
            cur.next = pre;
            pre=cur;
            cur=next;
        }
        return pre;
    }
}