202. Happy Number.md

202. Happy Number

Happy Number - LeetCode

Code1

class Solution {
    public boolean isHappy(int n) {
        int j = 0;  // Initialize a counter for the loop.

        // Perform the following steps at most 10 times to prevent infinite looping.
        while (j++ < 10) {
            int sum = 0;  // Initialize a variable to store the sum of squared digits.

            // Extract and process each digit of 'n' until it becomes 0.
            while (n != 0) {
                int num = n % 10;      // Get the last digit of 'n'.
                sum += num * num;      // Square the digit and add it to 'sum'.
                n /= 10;              // Remove the last digit from 'n'.
            }

            if (sum == 1) return true;  // If the sum is 1, 'n' is a happy number, return true.

            n = sum;  // Update 'n' to be the calculated sum for the next iteration.
        }

        return false;  // If 'n' doesn't become 1 after 10 iterations, it's not a happy number, so return false.
    }
}

Code2

class Solution {
    public boolean isHappy(int n) {
        int j = 0;
        while (j++ < 10)
        {
            int sum = 0 ;
            int length = (int) (Math.log10(n) + 1) , te = 1 , i = 0;
            while (i++ < length)
            {
                sum += Math.pow( (n/te)%10 , 2);
                te *= 10;
            }
            if (sum == 1) return true;
            n = sum ;
        }

        return false;
    }
}