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;
}