isPalindrome.cpp

/*
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.
*/

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

        long long reversed = 0;
        long long temp = x;

        while (temp != 0) {
            int digit = temp % 10;
            reversed = reversed * 10 + digit;
            temp /= 10;
        }

        return (reversed == x);
    }
};