我正在尝试用我最熟悉的编程语言C#模拟蒙提霍尔问题(因为我从Think Statistics一书中了解到,有个人只有在看到计算机模拟后才被说服)。我的情景是奖品位置是随机的(每次运行),我的选择也是随机的,而游戏主持人打开门的选择是随机的(如果我选了非奖励,则不能是随机的)。
然而令人惊讶的是,无论我是否换门,我的程序都能实现50:50的获胜几率。以下是代码(对于长度请原谅我):
然而令人惊讶的是,无论我是否换门,我的程序都能实现50:50的获胜几率。以下是代码(对于长度请原谅我):
class Program
{
static void Main(string[] args)
{
Random rand = new Random();
int noSwitchWins = RunGames(rand, false, 10000);
int switchWins = RunGames(rand, true, 10000);
Console.WriteLine(string.Format("If you don't switch, you will win {0} out of 1000 games.", noSwitchWins));
Console.WriteLine(string.Format("If you switch, you will win {0} out of 1000 games.", switchWins));
Console.ReadLine();
}
static int RunGames(Random rand, bool doSwitch, int numberOfRuns)
{
int counter = 0;
for (int i = 0; i < numberOfRuns; i++)
{
bool isWin = RunGame(rand, doSwitch);
if (isWin)
counter++;
}
return counter;
}
static bool RunGame(Random rand, bool doSwitch)
{
int prize = rand.Next(0, 2);
int selection = rand.Next(0, 2);
// available choices
List<Choice> choices = new List<Choice> { new Choice(), new Choice(), new Choice() };
choices[prize].IsPrize = true;
choices[selection].IsSelected = true;
Choice selectedChoice = choices[selection];
int randomlyDisplayedDoor = rand.Next(0, 1);
// one of the choices are displayed
var choicesToDisplay = choices.Where(x => !x.IsSelected && !x.IsPrize);
var displayedChoice = choicesToDisplay.ElementAt(choicesToDisplay.Count() == 1 ? 0 : randomlyDisplayedDoor);
choices.Remove(displayedChoice);
// would you like to switch?
if (doSwitch)
{
Choice initialChoice = choices.Where(x => x.IsSelected).FirstOrDefault();
selectedChoice = choices.Where(x => !x.IsSelected).FirstOrDefault();
selectedChoice.IsSelected = true;
}
return selectedChoice.IsPrize;
}
}
class Choice
{
public bool IsPrize = false;
public bool IsSelected = false;
}
这完全是出于我个人的兴趣,我用最熟悉和舒适的方式写下了它。请随意提出您自己的意见和批评,非常感谢!