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