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Palindrome Linked List

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Given the head of a singly linked list, return true if it is a palindrome or false otherwise.

class Solution:
    def isPalindrome(self, head: ListNode) -> 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

Posted by Jamie Meyer 7 months ago

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