Java for LeetCode 202 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
解题思路：

HashMap，JAVA实现如下：

    public boolean isHappy(int n) {
        HashMap<Integer,Boolean> hm=new HashMap<Integer,Boolean>();
        while(!hm.containsKey(n)&&n!=1){
        	hm.put(n, true);
        	n=HappyTime(n);
        }
        return n==1;
    }
   static public int HappyTime(int n){
    	int res=0;
    	while(n!=0){
    		res+=(n%10)*(n%10);
    		n/=10;
    	}
    	return res;
    }