Java 三门问题

public class ThreeGatesExp {

    private int N;
    public ThreeGatesExp(int N){

        if(N <= 0)
            throw  new IllegalArgumentException("N must be larger than 0");
        
        this.N = N;
    }

    public void run(boolean changDoor){

        int wins = 0;

        for(int i = 0; i < N; i ++){
            if(play(changDoor))
                wins ++;
        }
        System.out.println(changDoor ? "Change" : "Not Change");
        System.out.println("winning rate: " + (double)wins/N);
    }



    private boolean play(boolean changeDoor){
        // Door 012
        //哪扇有奖品 哪扇选定的
        int prizeDoor = (int)(Math.random() * 3);
        int playerChoice = (int)(Math.random() * 3);

        if( playerChoice == prizeDoor)
            return changeDoor ? false : true;
        else
            return changeDoor ? true : false;
    }


    public static void main(String[] args) {
        int N = 100000;
        ThreeGatesExp exp = new ThreeGatesExp(N);
        exp.run(true);
        System.out.println("Hello world!");
        exp.run(false);
    }
}