Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
The Monty Hall Problem with Haskell
Search
Mathias Verraes
May 04, 2016
Technology
0
2.7k
The Monty Hall Problem with Haskell
5min lightning talk for the SoCraTes Belgium meetup.
Mathias Verraes
May 04, 2016
Tweet
Share
More Decks by Mathias Verraes
See All by Mathias Verraes
On Being Explicit
mathiasverraes
0
3k
How to Find the Bar
mathiasverraes
1
2.1k
Designed Stickiness
mathiasverraes
1
2.2k
The World's Shortest and Most Chaotic Introduction to Event Storming
mathiasverraes
2
2.7k
Property Based Testing
mathiasverraes
1
2.7k
Towards Modelling Processes
mathiasverraes
3
5.8k
Modelling Heuristics
mathiasverraes
1
2.9k
Object Reorientation
mathiasverraes
6
2.8k
Small Controlled Experiments
mathiasverraes
1
4.1k
Other Decks in Technology
See All in Technology
Segment Anything Modelの最新動向:SAM2とその発展系
tenten0727
0
220
S3 Glacier のデータを Athena からクエリしようとしたらどうなるのか/try-to-query-s3-glacier-from-athena
emiki
0
180
Tableau API連携の罠!?脱スプシを夢見たはずが、逆に依存を深めた話
cuebic9bic
3
200
【CEDEC2025】大規模言語モデルを活用したゲーム内会話パートのスクリプト作成支援への取り組み
cygames
PRO
2
770
ホリスティックテスティングの右側も大切にする 〜2つの[はか]る〜 / Holistic Testing: Right Side Matters
nihonbuson
PRO
0
570
20250807_Kiroと私の反省会
riz3f7
0
120
生成AI導入の効果を最大化する データ活用戦略
ham0215
0
110
Google Agentspaceを実際に導入した効果と今後の展望
mixi_engineers
PRO
2
320
AI によるドキュメント処理を加速するためのOCR 結果の永続化と再利用戦略
tomoaki25
0
380
Oracle Cloud Infrastructure:2025年7月度サービス・アップデート
oracle4engineer
PRO
1
110
マルチモーダル基盤モデルに基づく動画と音の解析技術
lycorptech_jp
PRO
4
490
AIに目を奪われすぎて、周りの困っている人間が見えなくなっていませんか?
cap120
1
430
Featured
See All Featured
Save Time (by Creating Custom Rails Generators)
garrettdimon
PRO
31
1.3k
How To Stay Up To Date on Web Technology
chriscoyier
790
250k
The Psychology of Web Performance [Beyond Tellerrand 2023]
tammyeverts
48
2.9k
Understanding Cognitive Biases in Performance Measurement
bluesmoon
29
1.8k
Build The Right Thing And Hit Your Dates
maggiecrowley
37
2.8k
Helping Users Find Their Own Way: Creating Modern Search Experiences
danielanewman
29
2.8k
Intergalactic Javascript Robots from Outer Space
tanoku
272
27k
Templates, Plugins, & Blocks: Oh My! Creating the theme that thinks of everything
marktimemedia
31
2.5k
How to train your dragon (web standard)
notwaldorf
96
6.1k
YesSQL, Process and Tooling at Scale
rocio
173
14k
Building Applications with DynamoDB
mza
95
6.5k
Large-scale JavaScript Application Architecture
addyosmani
512
110k
Transcript
The Monty Hall Problem @mathiasverraes
None
None
None
None
None
Don't use thinking when you can use programming — Alan
Turing1 1 Supposedly
data Door = Goat | Car deriving (Eq, Show) type
Game = [Door]
newGame :: MonadRandom m => m Game newGame = shuffleM
[Car, Goat, Goat] newGames :: MonadRandom m => m [Game] newGames = replicateM 100 newGame
(|>) = flip ($) play :: Strategy -> Game ->
Door play strategy game = game |> pickDoor |> revealGoat |> strategy
pickDoor :: Game -> Game pickDoor = id -- Assume
we always pick -- the first door, it -- doesn't matter anyway.
revealGoat :: Game -> Game revealGoat [choice, Goat, x] =
[choice, x] revealGoat [choice, x, Goat] = [choice, x]
type Strategy = Game -> Door stay :: Strategy stay
[firstChoice, alternative] = firstChoice switch :: Strategy switch [firstChoice, alternative] = alternative
do game <- newGame return $ play stay game) --
Goat do game <- newGame return $ play switch game -- Car
playAll :: Strategy -> [Game] -> Int playAll strategy games
= map (play strategy) games |> filter (==Car) |> length
do gs <- newGames return $ playAll stay gs --
32 do gs <- newGames return $ playAll switch gs -- 68
None
module MontyHall where newGame :: MonadRandom m => m Game
newGame = shuffleM [Car, Goat, Goat] import System.Random.Shuffle newGames :: MonadRandom m => m [Game] import Control.Monad.Random.Class newGames = replicateM 100 newGame import Control.Monad pickDoor :: Game -> Game (|>) = flip ($) pickDoor = id data Door = Goat | Car deriving (Eq, Show) revealGoat :: Game -> Game type Game = [Door] revealGoat [choice, Goat, x] = [choice, x] type Strategy = Game -> Door revealGoat [choice, x, Goat] = [choice, x] play :: Strategy -> Game -> Door stay, switch :: Strategy play strategy game = stay [firstChoice, alternative] = firstChoice game switch [firstChoice, alternative] = alternative |> pickDoor |> revealGoat main :: IO() |> strategy main = do (stayCnt, switchCnt) <- do playAll :: Strategy -> [Game] -> Int gs <- newGames playAll strategy games = return (playAll stay gs, playAll switch gs) map (play strategy) games print ("Stay: " ++ show stayCnt) |> filter (==Car) print ("Switch: " ++ show switchCnt) |> length
Full source code: https://gist.github.com/mathiasverraes/ 3a31c912c6efb496566d55ee077dad6f Diagram: Curiouser http://www.curiouser.co.uk/monty/montyhall2.htm Images: AsapScience
http://youtube.com/watch?v=9vRUxbzJZ9Y Inspiration: F# Monty Hall problem by Yan Cui http://theburningmonk.com/2015/09/f-monty-hall-problem/
Thanks :-) @mathiasverraes