# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
#
# @param head ListNode类
# @return ListNode类
#
class Solution:
    def ReverseList(self, head: ListNode) -> ListNode:
        pre = None
        cur = head

        while cur:
            temp = cur.next
            cur.next = pre
            pre = cur
            cur = temp
        return pre