Monty Hall Problem - Weird Probability

montyhall.swift

import Foundation


//: Playground - noun: a place where people can play

import UIKit

func random(lessThan aNumber: Int) -> Int {
    return Int(arc4random_uniform(UInt32(aNumber)))
}

var firstWinCount = 0
var audienceWinCount = 0

for _ in 0..<1000 {

    let boxesCount = 3
    let priceBox = random(lessThan: boxesCount)
    let firstPicked = random(lessThan: boxesCount)
    let lastOpenedBox = Array(0..<boxesCount).first {
        $0 != priceBox && $0 != firstPicked
    }!


    // Left boxes always be 2, has or no price
    let leftBoxes: [Int]

    if firstPicked == priceBox {
        firstWinCount += 1
        leftBoxes = [priceBox, lastOpenedBox]
    } else {
        leftBoxes = [priceBox, firstPicked]
    }

    // Audience start picked
    let audiencePicked = leftBoxes[random(lessThan: leftBoxes.count)]
    if audiencePicked == priceBox {
        audienceWinCount += 1
    }
}

//😱😱😱
print(firstWinCount)
print(audienceWinCount)