[백준] 2331번 : 반복수열 - C#

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

using System;
using System.Collections;

class Program
{
    static int make(int a,int p){
        int sum=0;
        while(a>0){
            sum+=(int)Math.Pow(a%10,p);
            a/=10;
        }
        return sum;
    }
    
    static void Main() {
        ArrayList arr=new ArrayList();
        string[] s=Console.ReadLine().Split(' ');
        int a=int.Parse(s[0]);
        int p=int.Parse(s[1]);
        arr.Add(a);
        int num=a;
        while(true){
            num=make(num,p);
            
            if(arr.Contains(num)){
                int ans=arr.IndexOf(num);
                Console.Write(ans);
                break;
            }
            arr.Add(num);
        }
    }
}