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) :
        # write code here

        if not head:
            return None

        #先遍历链表中的元素
        L = []
        while head:
            L.append(head.val)
            head = head.next
        

        #反转链表的元素
        L = L[::-1]
        result = ListNode(L[0])
        #构造新的链表
        cur = result
        for  x in L[1:]:
            cur.next=ListNode(x)
            cur =cur.next
        cur.next=None
        return result