#7 Daily Problems -IsListPalindrome

Hey Guys, it’s my 7th day of solving one problem per day continously.This is a very small miles stone I have reached.
Problem:

Note: Try to solve this task in O(n) time using O(1) additional space, where n is the number of elements in l, since this is what you'll be asked to do during an interview.

Given a singly linked list of integers, determine whether or not it’s a palindrome.

Note: in examples below and tests preview linked lists are presented as arrays just for simplicity of visualization: in real data you will be given a head node l of the linked list

Example

• For l = [0, 1, 0], the output should be
  isListPalindrome(l) = true;
• For l = [1, 2, 2, 3], the output should be
  isListPalindrome(l) = false.

Input/Output

• [execution time limit] 3 seconds (java)
• [input] linkedlist.integer l
• A singly linked list of integers.
• Guaranteed constraints:
  0 ≤ list size ≤ 5 · 105,
  -109 ≤ element value ≤ 109.
• [output] boolean
• Return true if l is a palindrome, otherwise return false

Solution:

// Singly-linked lists are already defined with this interface:
// class ListNode<T> {
//   ListNode(T x) {
//     value = x;
//   }
//   T value;
//   ListNode<T> next;
// }
//
boolean isListPalindrome(ListNode<Integer> l) {
Boolean isPoly = true;
ListNode<Integer> firstLinkedList=l;
Stack<Integer> slist= new Stack<>();
while(firstLinkedList!=null){
slist.push(firstLinkedList.value);
firstLinkedList= firstLinkedList.next;
}
while(l!=null){
int value=slist.pop();
if(value==l.value){
isPoly=true;
}else{
isPoly=false;
break;
}
l=l.next;
}
return isPoly;
}

Hey guys thanks for seeing this and please give some valid suggestion because I will also learn from you.Ok, Let’s meet tomorrow.

Happy coding!

Buy me a coffee?
If you like this article, you can buy me a coffee. Thanks!