package isHappy202;
/*
* 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.
*/ public class Solution {
/*
* solution:
* 1
* 2-4-16-37-58-89-145-42-20-4
* 3-9-81-65-61
* 4
* 5-25-29-85-89
* 6-36-45-41-17-50
* 7-49-97-130-10
* 8-64-52-29
* 9-81-65
* so only 1 and 7 is "happy"
*/
public static boolean isHappy(int n) {
while(n/10>0){
int sum=0;
while(n/10>0){
sum+=Math.pow((n%10),2);
n=n/10;
}
sum+=Math.pow(n,2);
n=sum;
}
if (n==1||n==7)
return true;
return false;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(isHappy(23456));
}
}