Palindrome Linked List

palindromeLinkedList.py

class Solution:
    def isPalindrome(self, head):
        rhead = None
        slow = fast = head
        while fast and fast.next:
            fast = fast.next.next
            slow.next, slow, rhead = rhead, slow.next, slow
        if fast:
            slow = slow.next
        while rhead and rhead.val == slow.val:
            rhead = rhead.next
            slow = slow.next
        return not rhead