Happy Number

https://leetcode.com/problems/happy-number/

Write an algorithm to determine if a number 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, 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: 19 is a happy number

• 12 + 92 = 82
• 82 + 22 = 68
• 62 + 82 = 100
• 12 + 02 + 02 = 1

Credits:
Special thanks to @mithmatt and @ts for adding this problem and creating all test cases.

import java.util.HashSet;
import java.util.Set;

public class Solution {
    public static boolean isHappy(int n) {
    if(n==1){return true;}
    Set<Integer>set=new HashSet();
    int result=0;
        while(result!=1){
            result=0;
            String x=n+"";
            int len=x.length();
            for(int i=0;i<len;i++){
            char c=x.charAt(i);
            result+=(c-'0')*(c-'0');
            }
            if(set.contains(result)){return false;}
            set.add(result);
            n=result;
        }
        return true;
    }
    public static void main(String[]args){
    System.out.println(isHappy(19));
    }
}