反转链表

public class Solution {
    // 遍历，拿到一个节点处理一个
    public ListNode ReverseList(ListNode head) {
    ListNode prev = null;
        ListNode curt = head;
        while(curt != null){
            ListNode tmp = curt;
            curt = curt.next;
            tmp.next = prev;
            prev = tmp;
        }
        return prev;
    }
}