Archief - kansrekenen

class Program {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		int withoutchange =0;
		for (int i = 0;i<10000;i++)	
		{
			Game test = new Game();
			if(test.play(false))
				withoutchange++;
		}
		int withchange = 0;
		for (int i = 0;i<10000;i++)	
		{
			Game test = new Game();
			if(test.play(true))
				withchange++;
		}
		System.out.println("Number of successes WITH change: "+withchange+"\nNumber of successes without change: "+withoutchange);
	}
}

import java.util.ArrayList;

class Game {
	ArrayList doors = new ArrayList();
	ArrayList chosen = new ArrayList();
	int carpos, pos;
	public Game()
	{
		//Put one position RANDOM on true
		carpos = (int)Math.floor(Math.random()*3);
		for(int i =0;i<3;i++)
		{
			if(i==carpos)
			{
				doors.add(new Boolean(true));
			}
			else
			{
				doors.add(new Boolean(false));
			}
		}
	}
	
	///Return true if won, false if not
	public boolean play(boolean change)
	{
		//Let candidate pick one door RANDOM
		pos = (int)Math.floor(Math.random()*3);
		for(int i =0;i<3;i++)
		{
			if(i==pos)
			{
				chosen.add(new Boolean(true));
			}
			else
			{
				chosen.add(new Boolean(false));
			}
		}
		
		//Some initialization
		ArrayList removals = new ArrayList();
		int remove;
		//gamemaster must delete one random WRONG position:
		
		//List of possible doors:
		for (int i = 0,l=doors.size(); i < l; i++) 
		{
			if(i!=pos && i !=carpos ) removals.add(new Integer(i));
		}
		//Pick a door:
		if(removals.size() == 1)
		{
			remove = ((Integer)removals.get(0)).intValue();
		}
		else
		{
			// Player did choose correct one, so we can just pick one of the two other doors 
			remove = ((Integer)removals.get((int)Math.floor(Math.random()*2))).intValue();
		}
		
		//And remove it:
		doors.remove(remove);
		chosen.remove(remove);
		
		
		
		// Is player going to change?
		int finalpick;
		if(change)
		{
			if( ((Boolean)chosen.get(0)).booleanValue() )
			{
				finalpick=1;
			}
			else
				finalpick=0;
		}
		else
		{
			if( ((Boolean)chosen.get(0)).booleanValue() )
				finalpick=0;
			else
				finalpick=1;
		}
		return ((Boolean)doors.get(finalpick)).booleanValue();
	}
}