【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;    }}