package normal;

import java.util.HashSet;

/**
 * @program JavaBooks
 * @description: 202.快乐数
 * @author: mf
 * @create: 2019/11/06 10:15
 */


public class IsHappy {
    public static void main(String[] args) {
        System.out.println(isHappy(19));
        System.out.println(isHappy2(19));
    }

    /**
     * 递归，但有4的话，就一直循环，所以是4就false
     * @param n
     * @return
     */
    private static boolean isHappy(int n) {
        if (n == 1) return true;
        if (n != 4) {