【算法】快乐数202

快乐数202

import java.util.Set;
import java.util.HashSet;
import java.util.Scanner;


//快乐数202
public class HappyNumber202 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);

		System.out.print("快乐数判断：");
		if (new Solution().isHappy(input.nextInt())) {
			System.out.println("\n您输入的【是】快乐数！");
		}else {
			System.out.println("\n很抱歉，您输入的【不是】快乐数。");
		}
	}
}
class Solution {
    public boolean isHappy(int n) {
    	Set<Integer> set = new HashSet<>();
    	//前面是‘是’的退出条件，后面是‘不是’的退出条件
    	while(n != 1 && !set.contains(n)){
    		set.add(n);
    		//n变化
    		n = newNum(n);
    	}
    	return n == 1;
    }
    private int newNum(int origalNum){
    	int res = 0;
    	while(origalNum > 0){
    		int temp = origalNum % 10;
    		res += temp * temp;
    		origalNum /= 10;
    	}
    	return res;
    }
}