public static void main(String[] args) {
int stayWin = 0;
int switchWin = 0;
int stayFail = 0;
int swtichFail = 0;
int stay = 0;
int sswitch = 0;
boolean printEachResult = false;
int total = 1000;
for (int j = 0; j < total; j++) {
int doorWithPrize = getRandomNumberInRange(1, 3);
int choice = getRandomNumberInRange(1, 3);
List<String> otherDoors = new ArrayList<>();
for (int i = 1; i < 4; i++) {
if (i != choice) {
otherDoors.add(String.valueOf(i));
}
}
if (otherDoors.contains(String.valueOf(doorWithPrize))) {
// remove by object
otherDoors.remove(String.valueOf(doorWithPrize));
} else {
// remove by index
otherDoors.remove(getRandomNumberInRange(0, 1));
}
int doorToRemove = Integer.parseInt(otherDoors.get(0));
// print each result
if (printEachResult) {
System.out.println("Prize : " + doorWithPrize);
System.out.println("Choice : " + choice);
System.out.println("Remove : " + doorToRemove);
if (choice == doorWithPrize) {
System.out.println("Win");
} else {
System.out.println("Fail");
}
}
List<String> newDoors = new ArrayList<>();
for (int i = 1; i < 4; i++) {
if (i != doorToRemove) {
newDoors.add(String.valueOf(i));
}
}
int newChoiceIndex = getRandomNumberInRange(0, 1);
int newChoice = Integer.parseInt(newDoors.get(newChoiceIndex));
if (newChoice == choice) {
// stay
stay++;
if (doorWithPrize == choice) {
stayWin++;
} else {
stayFail++;
}
} else {
// switch
sswitch++;
if (doorWithPrize == newChoice) {
switchWin++;
} else {
swtichFail++;
}
}
}
float stayWinPercent = (float) stayWin / (float) stay * 100.f;
float stayFailPercent = (float) stayFail / (float) stay * 100.f;
float switchWinPercent = (float) switchWin / (float) sswitch * 100.f;
float switchFailPercent = (float) swtichFail / (float) sswitch * 100.f;
System.out.println("Stay => " + stay);
System.out.println("Win : " + stayWinPercent);
System.out.println("Fail : " + stayFailPercent);
System.out.println("Switch => " + sswitch);
System.out.println("Win : " + switchWinPercent);
System.out.println("Fail : " + switchFailPercent);
}
private static int getRandomNumberInRange(int min, int max) {
if (min >= max) {
throw new IllegalArgumentException("max must be greater than min");
}
Random r = new Random();
return r.nextInt((max - min) + 1) + min;
}
Result
Stay => 499868 Win : 33.314995 Fail : 66.685005 Switch => 500132 Win : 66.766174 Fail : 33.233826