# 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 != None: nxt = cur.next cur.next = pre pre = cur cur = nxt return pre