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package main
import "fmt"
import "math/rand"
import "time"
const NoOfGames = 10000
const NoOfDoors = 3
func main() {
fmt.Printf("Monty Hall %d-door experiment\n", NoOfDoors)
s := rand.NewSource(time.Now().Unix())
r := rand.New(s)
switchStrategyWins := 0
holdStrategyWins := 0
for i := 0; i < NoOfGames; i++ {
// randomly choose a door behind which there's a prize
prizeDoor := r.Intn(NoOfDoors)
// player picks a door at random
playerChoice := r.Intn(NoOfDoors)
fmt.Printf("Prize door: %d, player choice: %d", prizeDoor, playerChoice)
// host randomly opens one door (which is not the player chosen door and not the prize door)
var openDoor int
for openDoor = r.Intn(NoOfDoors); openDoor == playerChoice || openDoor == prizeDoor; openDoor = r.Intn(NoOfDoors) {}
fmt.Printf(", host opens door: %d", openDoor)
if (playerChoice == prizeDoor) {
// first strategy - don't change the original choice
holdStrategyWins++
fmt.Printf(" - HOLD wins\n")
} else {
// second strategy - change the choice to another door
var newChoice int
for newChoice = r.Intn(NoOfDoors); newChoice == playerChoice || newChoice == openDoor; newChoice = r.Intn(NoOfDoors) {}
if (newChoice == prizeDoor) {
switchStrategyWins++
fmt.Printf(" - SWITCH wins\n")
} else {
fmt.Printf(" - NO STRATEGY wins\n")
}
}
}
fmt.Printf("Hold strategy wins: %d, win probability: %3.2f\n", holdStrategyWins, float32(holdStrategyWins) / NoOfGames)
fmt.Printf("Switch strategy wins: %d, win probability: %3.2f\n", switchStrategyWins, float32(switchStrategyWins) / NoOfGames)
}
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