java - ArrayList在程序中变得巨大以猜测1000-9999之间的数字

Question

程序猜测 1000-9999 之间的数字，用户说出猜测的数字中有多少是正确的数字并且位于正确的位置(但仅输入正确数字的数量)。然而，每次我尝试时，我都会得到一大堆重复项，但只有一个正确数字的条目。我将如何确保我的 ArrayList 中没有重复项？我更希望被指出正确的方向，而不仅仅是给出答案，谢谢!这是我的代码(主要方法是我的教授编写的，我不需要更改它):

import java.util.ArrayList;
import java.util.Random;
import javax.swing.JOptionPane;

public class GuessingGame {

    public int numGuesses = 0;
    public ArrayList<Integer> numbers = new ArrayList<Integer>();
    public int guess;

    public GuessingGame ( ) {
        for (int i = 1000; i < 10000; i++) {
            numbers.add(i);
        }
        //populating numbers ArrayList

    }

    public int myGuessIs() {
        numGuesses++;
        //increases number of guesses
        int tempIndex = (int) (Math.random() * numbers.size());
        int myguess = numbers.get(tempIndex);
        //creates a new guess
        guess = myguess;
        //sets global variable
        return myguess;
    }

    public int totalNumGuesses() {
        return numGuesses;
        //returns guesses needed to reach solution
    }

    public void updateMyGuess(int nmatches) {
        ArrayList<Integer> temp = new ArrayList<Integer>();
        ArrayList<Integer> temp2 = new ArrayList<Integer>();
        int first = guess/1000;
        int second = (guess/100)%10;
        int third = (guess/10)%10;
        int fourth = guess%10;
        //variables for each digit of guess
        if (nmatches == 1) {
            for (int i = 0; i < numbers.size(); i++) {
                if (numbers.get(i)/1000 == first) temp.add(numbers.get(i));
                if ((numbers.get(i)/100)%10 == second) temp.add(numbers.get(i));
                if ((numbers.get(i)/10)%10 == third) temp.add(numbers.get(i));
                if (numbers.get(i)%10 == fourth) temp.add(numbers.get(i));
            }
            numbers.clear();
            numbers.addAll(temp);
        }else if (nmatches == 2) {
            for (int i = 0; i < numbers.size(); i++) {
                if (numbers.get(i)/1000 == first &&
                    (numbers.get(i)/100)%10 == second) temp.add(numbers.get(i));
                if (numbers.get(i)/1000 == first &&
                    (numbers.get(i)/10)%10 == third) temp.add(numbers.get(i));
                if (numbers.get(i)/1000 == first &&
                    numbers.get(i)%10 == fourth) temp.add(numbers.get(i));
                if ((numbers.get(i)/100)%10 == second &&
                    (numbers.get(i)/10)%10 == third) temp.add(numbers.get(i));
                if ((numbers.get(i)/100)%10 == second &&
                    numbers.get(i)%10 == fourth) temp.add(numbers.get(i));
                if ((numbers.get(i)/10)%10 == third &&
                    numbers.get(i)%10 == fourth) temp.add(numbers.get(i));
            }
            numbers.clear();
            numbers.addAll(temp);
        }else if (nmatches == 3) {
            for (int i = 0; i < numbers.size(); i++) {
                if (numbers.get(i)/1000 == first && (numbers.get(i)/100)%10 == second
                    && (numbers.get(i)/10)%10 == third) temp.add(numbers.get(i));
                if (numbers.get(i)/1000 == first && (numbers.get(i)/10)%10 == third
                    && numbers.get(i)%10 == fourth) temp.add(numbers.get(i));
                if ((numbers.get(i)/100)%10 == second && (numbers.get(i)/10)%10 == third
                    && numbers.get(i)%10 == fourth) temp.add(numbers.get(i));
            }
            numbers.clear();
            numbers.addAll(temp);
        }else {
            for (int i = 0; i < numbers.size(); i++) {
                if (numbers.get(i)/1000 == first) temp2.add(numbers.get(i));
                if ((numbers.get(i)/100)%10 == second) temp2.add(numbers.get(i));
                if ((numbers.get(i)/10)%10 == third) temp2.add(numbers.get(i));
                if (numbers.get(i)%10 == fourth) temp2.add(numbers.get(i));
            }
            numbers.removeAll(temp2);
        }
        //creates new smaller ArrayList with better guesses
        //sets numbers as the smaller list
        //update the guess based on the number of matching digits claimed by the user
        for (int i = 0; i < numbers.size(); i++) {
            System.out.println(numbers.get(i) + "   " + i);
        } //troubleshooting

    }

    public static void main(String[] args) {



        GuessingGame gamer = new GuessingGame( );

        JOptionPane.showMessageDialog(null, "Think of a number between 1000 and 9999.\n Click OK when you are ready...", "Let's play a game", JOptionPane.INFORMATION_MESSAGE);
        int numMatches = 0;
        int myguess = 0;

        do {
            myguess = gamer.myGuessIs();
            if (myguess == -1) {
                JOptionPane.showMessageDialog(null, "I don't think your number exists.\n I could be wrong though...", "Mistake", JOptionPane.INFORMATION_MESSAGE);
                System.exit(0);
            }
            String userInput = JOptionPane.showInputDialog("I guess your number is " + myguess + ". How many digits did I guess correctly?");
            // quit if the user input nothing (such as pressed ESC)
            if (userInput == null)
                System.exit(0);
            // parse user input, pop up a warning message if the input is invalid
            try {
                numMatches = Integer.parseInt(userInput.trim());
            }
            catch(Exception exception) {
                JOptionPane.showMessageDialog(null, "Your input is invalid. Please enter a number between 0 and 4", "Warning", JOptionPane.WARNING_MESSAGE);
                numMatches = 0;
            }
            // the number of matches must be between 0 and 4
            if (numMatches < 0 || numMatches > 4) {
                JOptionPane.showMessageDialog(null, "Your input is invalid. Please enter a number between 0 and 4", "Warning", JOptionPane.WARNING_MESSAGE);
                numMatches = 0;
            }
            if (numMatches == 4)
                break;
            // update based on user input
            gamer.updateMyGuess(numMatches);

        } while (true);

        // the game ends when the user says all 4 digits are correct
        System.out.println("Aha, I got it, your number is " + myguess + ".");
        System.out.println("I did it in " + gamer.totalNumGuesses() + " turns.");
    }
}

Answer 1

使用不允许重复的数据结构来代替ArrayList:Set。