import java.util.*;

public class Main {

    /*
       字符猜位置游戏;
       每次提交只能被告知答对几个位置;
       根据提示答对的位置数推测出每个字符对应的正确位置;
     */
    public static void main(String[] args) {

        char startChar = 'A';

        int gameLength = 8;
        List<String> ballList = new ArrayList<>();

        String endChar = "";
        for (int i = 0; i < gameLength; i++) {
            endChar = String.valueOf((char)((int)startChar + i));
            ballList.add(endChar);
        }

        String quest;
        StringBuilder anserString = new StringBuilder();

        for (int i = 0; i < gameLength; i++) {
            // 组装答案
            anserString.append(getTempAnserStr(ballList));
        }
        quest = anserString.toString();

        String anser = "";
        System.out.println("游戏开始： 共"+gameLength+"位," + "从"+ startChar + "到" + endChar);
        Scanner sc = new Scanner(System.in);
        int ansNum = 0;
        while(!evaAnser(anser,quest)) {
            anser = sc.next();
            ansNum++;
        };

        System.out.println("回答正确！  答案是：" + quest);
        System.out.println("回答次数：" + ansNum);

    }

    private static boolean evaAnser(String anser, String quest) {

        if (anser == null || anser.isEmpty()) {
            return false;
        }
        int correctNums = 0;

        char[] questArr = quest.toCharArray();
        char[] anserArr = anser.toCharArray();

        for (int i = 0; i < anserArr.length; i++) {
            if (questArr[i] == anserArr[i]) {
                correctNums++;
            }
        }

        System.out.println("correct: " + correctNums);

        return correctNums == quest.length();
    }

    // 获取随机字符
    private static String getTempAnserStr(List<String> balls) {
        Random random = new Random();
        int randomNumber = random.nextInt(balls.size());
        String tempBall = balls.get(randomNumber);
        balls.remove(randomNumber);
        return tempBall;
    }

}

游戏示例：