# 234. Palindrome Linked List """ given the head of a signly linked list return true if it is a palindrome or false otherwise. """ # Definition for singly-linked list. class ListNode(object): def __init__(self, val=0, next=None): self.val = val self.next = next class Solution(object): def isPalindrome(self, head): """ :type head: ListNode :rtype: bool """ slow, fast, prev = head, head, None while fast and fast.next: slow, fast = slow.next, fast.next.next prev, slow, prev.next = slow, slow.next, None while slow: slow.next, prev, slow = prev, slow, slow.next fast, slow = head, prev while slow: if fast.val != slow.val: return False fast, slow = fast.next, slow.next return True if __name__ == "__main__": obj = Solution() h1 = ListNode() h2 = ListNode()