题解 | 反转链表

# 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:
        current=head
        su_node=None
        while (current is not None):
            next_node=current.next
            current.next=su_node
            su_node=current
            current=next_node
        return su_node  # 最后prev就是新链表的头节点




        # write code here