CODEWITHSUNDEEP
pythonlinked-list
user15552191
user15552191

Reputation:

Does my solution work to determine palindrome for Linked List?

I have written some code below to determine is a Linked List is a palindrome, but when I run it through tests cases it simply times out. Any idea what is wrong with the code? Thanks

def isPalindrome(self, head: ListNode) -> bool:
    if head == None:
        return True

    length_ll = 0
    curr = head
    while curr:
        length_ll +=1
        curr = curr.next


    mid_point = length_ll//2

    head2 = head
    for _ in range(mid_point):
        head2 = head2.next             


    prev = head2
    curr = head2
    nex = head2.next

    while nex:
        curr = nex
        curr.next = prev
        nex = nex.next
        prev = curr
    head2.next = None


    curr = head
    curr2 = head2
    
    while curr or curr2:
        if curr2.val != curr.val:
            return False
        else:
            curr = curr.next
            curr2 = curr2.next

    return True

Upvotes: 0

Views: 26

Answers (1)

Dmitry
Dmitry

Reputation: 146

Your 3rd while statement is infinite (if curr2.val == curr.val it will never stop)

Upvotes: 1

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