Palindrome Number

Problem

Given an integer x, return true if x is a palindrome, and false otherwise.

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

Constraints

• -231 <= x <= 231 -1

Solution

The problem Palindrome Number can be solved by reversing digits of given integer and checking if it’s the same as the original. One thing to note here is that since negative integers can never be a palindrome, it should be handled at the beginning.

Implementation

class Solution
{
  public:
    bool isPalindrome(int x)
    {
        if (x < 0)
            return false;

        long int rev = 0;
        int y = x;

        while (y)
        {
            rev = rev * 10 + y % 10;
            y /= 10;
        }

        return (long int)x == rev;
    }
};