Naga Vara Pradeep, Yendluri

Palindrome Number

Steps

1. Create a temporary variable to store the incoming number for later.
2. Create a variable to store the reconstructed reverse of the given number and initialize it to 0.
3. We take the idea of dividing (%) a number by 10 that gives the units digit as remainder. (Main step to remember while answering problems like this)
4. So, we keep a condition in while loop that number must not be 0.
5. In while loop we take a temporary variable to store the unit's digit of the given number (this will be updated at end of loop)
6. Now use the temp var like below
7. reverseNumber = reverseNumber * 10 + temporaryVariable
8. At the end of loop we divide the given number n / 10 and update it to n, i.e n = n/10. We do this until we reach 0 and exit the loop.
9. After that we can check whether the reverseNumber == n to return boolean value.

Java Implementation

class Solution {
    public boolean isPalindrome(int x) {
        int temp = x;
        int reverseNumber = 0;
        if (x < 0) {
            return false;
        }

        while (x != 0) {
            int zeroUnitDigit = x % 10;
            reverseNumber = reverseNumber * 10 + zeroUnitDigit;
            x = x / 10;
        }
        return (reverseNumber == temp) ? true : false;
    }
}