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) {
            return null;
        }
        ListNode h = head;
        head = head.next;
        h.next = null;
        ListNode cur = head;
        while(cur != null) {
            head = head.next;
            cur.next = h;
            h = cur;
            cur = head;
        }
        return h;
    }
}