题解 | #判断一个链表是否为回文结构#

# 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 the head
# @return bool布尔型
#
class Solution:
    def isPail(self , head: ListNode) -> bool:
        # write code here
        raw_head = head
        reversal = None
        previous = None
        # 创建一个逆序链表和原链表进行比较。如果两者逐位相同，则是回文结构。
        while head:
            reversal = ListNode(head.val)
            reversal.next = previous
            previous = reversal
            head = head.next
        
        # 进行逐位比较。
        while raw_head:
            if raw_head.val != reversal.val:
                return False
            raw_head = raw_head.next
            reversal = reversal.next

        return True