Monty Hall problem: Difference between revisions

<syntaxhighlight lang="chapel">use Random;

param doors: int = 3;

config const games: int = 1000;

config const maxTasks = 32;

var numTasks = 1;

while( games / numTasks > 1000000 && numTasks < maxTasks ) do numTasks += 1;

const tasks = 1..#numTasks;

const games_per_task = games / numTasks ;

const remaining_games = games % numTasks ;

var wins_by_stay: [tasks] int;

coforall task in tasks {

var rand = new RandomStream();

for game in 1..#games_per_task {

var player_door = (rand.getNext() * 1000): int % doors ;

var winning_door = (rand.getNext() * 1000): int % doors ;

if player_door == winning_door then

wins_by_stay[ task ] += 1;

}

if task == tasks.last then {

for game in 1..#remaining_games {

var player_door = (rand.getNext() * 1000): int % doors ;

var winning_door = (rand.getNext() * 1000): int % doors ;

if player_door == winning_door then

wins_by_stay[ task ] += 1;

}

}

var total_by_stay = + reduce wins_by_stay;

var total_by_switch = games - total_by_stay;

var percent_by_stay = ((total_by_stay: real) / games) * 100;

var percent_by_switch = ((total_by_switch: real) / games) * 100;

writeln( "Wins by staying: ", total_by_stay, " or ", percent_by_stay, "%" );

writeln( "Wins by switching: ", total_by_switch, " or ", percent_by_switch, "%" );

if ( total_by_stay > total_by_switch ){

writeln( "Staying is the superior method." );

} else if( total_by_stay < total_by_switch ){

writeln( "Switching is the superior method." );

} else {

writeln( "Both methods are equal." );

}

</syntaxhighlight>

Wins by staying: 354 or 35.4%

Wins by switching: 646 or 64.6%

Switching is the superior method.