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 later = null;
        ListNode curr = head;
        while(curr != null){
            ListNode next = curr.next;
            curr.next = later;
            later = curr;
            curr = next;
        }
        
        return later;
    }
}