11.4 Palindrome Number (Easy)

Determine whether an integer is a palindrome. Do this without extra space.

A palindrome integer is an integer x for which reverse(x) = x where reverse(x) is x with its digit reversed. Negative numbers are not palindromic.

Example :

Input : 12121 Output : True

Input : 123 Output : False

https://leetcode.com/problems/palindrome-number/

https://www.interviewbit.com/problems/palindrome-integer/

• Use the same logic as 11.2 Reverse Integer. i.e. you first reverse the integer, then compare if the reversed integer is the same is the orgional input.

• Time O(log N)

  public class Solution {
    public boolean isPalindrome(int input) {
  
        int number = input;
        int rev = 0;
        int rmd = 0;
        while (number > 0) {
            rmd = number % 10;
            rev = rev * 10 + rmd;
            number = number / 10;
        }
  
        return (rev == input);
    }