import java.util.*;
 
public class MontyHall 
{
	public static void main(String[] args)
	{
		Scanner key = new Scanner(System.in);
		Random gen = new Random();
 
		System.out.print("Enter number of trials to run: ");
		int NUMOFTRIALS = key.nextInt();
		System.out.print("Stay Always (1) or Switch Always (2): ");
		int choice = key.nextInt();
		int numCorrect = 0;
		int pick,ans,show;
		ArrayList<Integer> doors = new ArrayList<Integer>();
 
		if(choice == 1) // always stay
		{
			for(int i = 0; i < NUMOFTRIALS; i++)
			{
				doors.clear();
				doors.add(1);
				doors.add(2);
				doors.add(3);
 
				pick = gen.nextInt(3);
				ans = gen.nextInt(3);
 
				doors.remove(ans);
 
				if(!doors.contains(pick)) show = doors.get(0);
				else
				{
					if(doors.get(0) == pick) show = doors.get(1);
					else show = doors.get(0);
				}
 
				if(show == pick) System.out.println("Something is wrong!!!");
				if(pick == ans) numCorrect++;
			}
		}
		else if(choice == 2) // always switch
		{
			int other = 22;
			for(int i = 0; i < NUMOFTRIALS; i++)
			{
				doors.clear();
				doors.add(0);
				doors.add(1);
				doors.add(2);
 
				pick = gen.nextInt(3);
				ans = gen.nextInt(3);
 
				doors.remove(ans);
 
				if(!doors.contains(pick)) 
				{
					int ran = gen.nextInt(2);
					show = doors.get(ran);
 
					if(ran == 1)
						other = doors.get(0);
					if(ran == 0)
						other = doors.get(1);
				}
				else
				{
					if(doors.get(0) == pick) 
					{
						show = doors.get(1);
						other = ans;
 
					}
					else
					{
						show = doors.get(0);
						other = ans;
 
					}
 
				}
 
				if(show == pick || other == 22) System.out.println("Something is wrong!!!");
 
				pick = other;
 
				if(pick == ans)numCorrect++;
			}
		}
		double percCorr = (double)numCorrect/(double)NUMOFTRIALS;
		System.out.printf("\n%.2f%s correct answers.", percCorr*100, "%");
	}
}