[LeetCode] (#202) Happy Number

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, 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.

Return True if n is a happy number, and False if not.

 

Example: 

Input: 19

Output: true

Explanation: 12 + 92 = 82 82 + 22 = 68 62 + 82 = 100 12 + 02 + 02 = 1

 

 

class Solution {

	public static boolean isHappy( int n ) {
		int t = n, sum = 0;
		while( true ) {
			if( sum == 1 ) return true;
			sum = 0;
			while( t > 0 ) {
	        		sum += (t%10)*(t%10);
	        		t/=10;
	        	}
			if( sum == 4 ) return false;
			t = sum;
		}
	}
}