[백준] 2331번 : 반복수열 - Java(자바)

https://www.acmicpc.net/problem/2331

import java.util.*;
public class Main {
    static int make(int a, int p){
        int sum=0;
        while(a>0){
            sum+=Math.pow(a%10,p);
            a/=10;
        }
        return sum;
    }
    
    public static void main(String args[]) {
        ArrayList<Integer> arr=new ArrayList<>();
        Scanner s=new Scanner(System.in);
        int a=s.nextInt();
        int p=s.nextInt();
        arr.add(a);
        while(true){
            int m=arr.get(arr.size()-1);
            int num=make(m,p);
             
            if(arr.contains(num)){
                int ans=arr.indexOf(num);
                System.out.print(ans);
                break;
            }
            arr.add(num);
        }
    }
}