PalindromeNumber.java

/* 
problem link: https://leetcode.com/problems/palindrome-number/
9. Palindrome Number
Solved
Easy
Topics
Companies
Hint
Given an integer x, return true if x is a 
palindrome
, and false otherwise.

 

Example 1:

Input: x = 121
Output: true
Explanation: 121 reads as 121 from left to right and from right to left.
Example 2:

Input: x = -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
Example 3:

Input: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
 

Constraints:

-231 <= x <= 231 - 1
 

Follow up: Could you solve it without converting the integer to a string?*/

public class PalindromeNumber {

    public boolean isPalindrome(int x) {
        int lastDigit;
        int rev = 0;
        int check = x;
        while (x > 0) {
            lastDigit = x % 10;
            rev = (rev * 10) + lastDigit;
            x /= 10;
        }
        return rev == check;
    }
}