Problem Challenge 1

We'll cover the following

- - Palindrome LinkedList (medium)
  - Try it yourself

Palindrome LinkedList (medium) #

Given the head of a Singly LinkedList, write a method to check if the LinkedList is a palindrome or not.

Your algorithm should use constant space and the input LinkedList should be in the original form once the algorithm is finished. The algorithm should have $O(N)$ time complexity where ‘N’ is the number of nodes in the LinkedList.

Example 1:

Input: 2 -> 4 -> 6 -> 4 -> 2 -> null
Output: true

Example 2:

Input: 2 -> 4 -> 6 -> 4 -> 2 -> 2 -> null
Output: false

Try it yourself #

Try solving this question here:

Java

Python3

C++

class Node:
  def __init__(self, value, next=None):
    self.value = value
    self.next = next
 
def is_palindromic_linked_list(head):
  # TODO: Write your code here
  return False
 
def main():
  head = Node(2)
  head.next = Node(4)
  head.next.next = Node(6)
  head.next.next.next = Node(4)
  head.next.next.next.next = Node(2)
 
  print("Is palindrome: " + str(is_palindromic_linked_list(head)))
 
  head.next.next.next.next.next = Node(2)
  print("Is palindrome: " + str(is_palindromic_linked_list(head)))
 
main()

Output

0.468s

Is palindrome: False Is palindrome: False

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Middle of the LinkedList (easy)

Solution Review: Problem Challenge 1