Happy Number - LeetCode

A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.


Example: 

Input: 19
Output: true
Explanation: 
12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1

Here the solution has to be done with in-build method. If we squaring the sum of each digit it will end up at 1, but in another case if sum is 4 it will be on loop and doesn't end. So we have to break the loop at 1 or 4. If 1 it is happy number else it is not a happy number.

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class Solution {
    public boolean isHappy(int n) {
        int sum=0, t1;
        while(sum >= 0){
            sum = 0;
            while(n != 0){
                t1 = n%10;
                sum = sum + (t1*t1);
                n/=10;
            }
            if(sum == 1 || sum ==4){
                break;
            }
            n = sum;
        }
        if(sum == 1 )
            return true;
        else
            return false;
      
    }
}

Happy Coding..!!😍 

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