【Java】happyNumber，

【Java】happyNumber，

/**
 * Created on 16/6/4.
 */
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
public class happyNumber {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        System.out.println(isHappyNumber(n));
    }

    public static boolean isHappyNumber(int n) {
        Set<Integer> x = new HashSet<>();
        while (n != 1) {
            if (x.contains(n)) {
                return false;
            }
            x.add(n);
            int sum = 0;
            while (n != 0) {
                int remainder = n % 10;
                sum += Math.pow(remainder, 2);
                n /= 10;
            }
            n = sum;
        }
        return true;
    }
}