DAY1P1.md

Happy Number

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• Question:

Write an algorithm to determine if a number n is happy.

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.
• 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.

Return true if n is a happy number, and false if not.

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• Example:

Input: n = 19

Output: true

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• Solution:

Code :

class Solution {
    public boolean isHappy(int n) {
        if(n<=0)
            return false;
        
        while(true)
        {
            int sum=0;
            while(n!=0)
            {
            // int sum=0;
            sum=sum+(n%10)*(n%10);
            n=n/10;
            }
            if(sum/10==0)
            {
                if(sum==1||sum==7)
                    return true;
                else
                    return false;
            }
        n=sum;
    }
}
}