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