MathSystem2/src/main/java/com/example/mathsystemtogether/ChoiceQuestionGenerator.java

package com.example.mathsystemtogether;

import java.util.*;

/**
 * 选择题生成器
 */
public class ChoiceQuestionGenerator {
    private final Random random = new Random();
    private final int MAX_OPERAND_VALUE = 50;  // 降低数值范围，便于计算
    private final int MIN_OPERAND_VALUE = 1;

    /**
     * 生成指定数量的选择题
     */
    public List<Question> generateQuestions(Level level, int count) {
        List<Question> questions = new ArrayList<>();
        Set<String> usedQuestions = new HashSet<>();

        int attempts = 0;
        int maxAttempts = count * 100; // 最大尝试次数

        while (questions.size() < count && attempts < maxAttempts) {
            Question question = generateSingleQuestion(level, questions.size() + 1);
            String questionKey = question.getQuestionText();

            if (!usedQuestions.contains(questionKey)) {
                usedQuestions.add(questionKey);
                questions.add(question);
            }
            attempts++;
        }

        return questions;
    }

    /**
     * 生成单个选择题
     */
    private Question generateSingleQuestion(Level level, int questionNumber) {
        switch (level) {
            case 小学:
                return generatePrimaryQuestion(questionNumber);
            case 初中:
                return generateJuniorQuestion(questionNumber);
            case 高中:
                return generateSeniorQuestion(questionNumber);
            default:
                return generatePrimaryQuestion(questionNumber);
        }
    }

    /**
     * 生成小学题目
     */
    private Question generatePrimaryQuestion(int questionNumber) {
        // 随机选择运算符号数量（1-3个）
        int operatorCount = 1 + random.nextInt(3);
        
        // 生成复合运算表达式
        String[] expression = generateCompoundExpression(operatorCount);
        String questionText = expression[0];
        int correctAnswer = Integer.parseInt(expression[1]);

        // 生成错误选项
        List<Integer> options = generateWrongOptions(correctAnswer);
        options.add(correctAnswer);
        Collections.shuffle(options);

        return new Question(questionText,
                          String.valueOf(options.get(0)),
                          String.valueOf(options.get(1)),
                          String.valueOf(options.get(2)),
                          String.valueOf(options.get(3)),
                          String.valueOf(correctAnswer),
                          questionNumber);
    }

    /**
     * 生成初中题目
     */
    private Question generateJuniorQuestion(int questionNumber) {
        // 随机选择运算符号数量（1-3个）
        int operatorCount = 1 + random.nextInt(3);
        
        // 30%概率生成纯平方/开方题目，70%概率生成包含平方/开方的复合运算题目
        if (random.nextDouble() < 0.3) {
            // 生成纯平方或开方题目
            if (random.nextBoolean()) {
                // 平方题目
                int a = MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE);
                String questionText = String.format("%d² = ?", a);
                int correctAnswer = a * a;
                List<Integer> options = generateWrongOptions(correctAnswer);
                options.add(correctAnswer);
                Collections.shuffle(options);

                return new Question(questionText,
                                  String.valueOf(options.get(0)),
                                  String.valueOf(options.get(1)),
                                  String.valueOf(options.get(2)),
                                  String.valueOf(options.get(3)),
                                  String.valueOf(correctAnswer),
                                  questionNumber);
            } else {
                // 开方题目
                int perfectSquare = (int) Math.pow(random.nextInt(10) + 1, 2);
                String questionText = String.format("√%d = ?", perfectSquare);
                int correctAnswer = (int) Math.sqrt(perfectSquare);
                List<Integer> options = generateWrongOptions(correctAnswer);
                options.add(correctAnswer);
                Collections.shuffle(options);

                return new Question(questionText,
                                  String.valueOf(options.get(0)),
                                  String.valueOf(options.get(1)),
                                  String.valueOf(options.get(2)),
                                  String.valueOf(options.get(3)),
                                  String.valueOf(correctAnswer),
                                  questionNumber);
            }
        } else {
            // 生成包含平方/开方的复合运算表达式（确保包含平方或开方）
            String[] expression = generateJuniorCompoundExpressionWithGuarantee(operatorCount);
            String questionText = expression[0];
            int correctAnswer = Integer.parseInt(expression[1]);

            // 生成错误选项
            List<Integer> options = generateWrongOptions(correctAnswer);
            options.add(correctAnswer);
            Collections.shuffle(options);

            return new Question(questionText,
                              String.valueOf(options.get(0)),
                              String.valueOf(options.get(1)),
                              String.valueOf(options.get(2)),
                              String.valueOf(options.get(3)),
                              String.valueOf(correctAnswer),
                              questionNumber);
        }
    }

    /**
    * 生成高中题目
    */
    private Question generateSeniorQuestion(int questionNumber) {
        // 随机选择运算符号数量（1-3个）
        int operatorCount = 1 + random.nextInt(3);
        
        // 30%概率生成纯三角函数题目，70%概率生成包含三角函数的复合运算题目
        if (random.nextDouble() < 0.3) {
            // 生成纯三角函数题目
            int[] commonAngles = {0, 30, 45, 60, 90, 120, 135, 150, 180, 210, 225, 270, 300, 315, 330};
            int angle = commonAngles[random.nextInt(commonAngles.length)];
            String[] functions = {"sin", "cos", "tan"};
            String function = functions[random.nextInt(functions.length)];

            String questionText = String.format("%s(%d°) = ?", function, angle);
            double result = calculateTrigFunction(function, angle);

            // 生成选项
            List<String> options = generateTrigOptions(result);
            // 使用格式化后的值作为正确答案，确保与选项一致
            String correctAnswer = formatTrigValue(result);

            // 随机打乱选项
            Collections.shuffle(options);

            return new Question(questionText,
                    options.get(0),
                    options.get(1),
                    options.get(2),
                    options.get(3),
                    correctAnswer,
                    questionNumber);
        } else {
            // 生成包含三角函数的复合运算表达式（确保包含三角函数）
            String[] expression = generateSeniorCompoundExpressionWithGuarantee(operatorCount);
            String questionText = expression[0];
            int correctAnswer = Integer.parseInt(expression[1]);

            // 生成错误选项
            List<Integer> options = generateWrongOptions(correctAnswer);
            options.add(correctAnswer);
            Collections.shuffle(options);

            return new Question(questionText,
                              String.valueOf(options.get(0)),
                              String.valueOf(options.get(1)),
                              String.valueOf(options.get(2)),
                              String.valueOf(options.get(3)),
                              String.valueOf(correctAnswer),
                              questionNumber);
        }
}

/**
 * 生成三角函数题目的选项
 */
private List<String> generateTrigOptions(double correctAnswer) {
    List<String> options = new ArrayList<>();
    Set<String> usedOptions = new HashSet<>();

    // 格式化正确答案，保留适当的小数位数
    String formattedCorrectAnswer = formatTrigValue(correctAnswer);
    options.add(formattedCorrectAnswer);
    usedOptions.add(formattedCorrectAnswer);

    // 添加常见三角函数值作为错误选项
    String[] commonValues = {"0", "0.5", "0.71", "0.87", "1", "1.73", "-0.5", "-0.71", "-0.87", "-1", "-1.73", "undefined"};
    List<String> commonValuesList = new ArrayList<>(Arrays.asList(commonValues));

    // 打乱常见值列表
    Collections.shuffle(commonValuesList);

    // 添加错误选项
    int wrongOptionsNeeded = 3;
    for (String value : commonValuesList) {
        if (wrongOptionsNeeded <= 0) break;
        // 确保不添加与正确答案相同的选项
        if (!usedOptions.contains(value) && !value.equals(formattedCorrectAnswer)) {
            options.add(value);
            usedOptions.add(value);
            wrongOptionsNeeded--;
        }
    }

    // 如果还需要更多选项，则生成接近正确答案的选项
    while (options.size() < 4) {
        String wrongOption = generateNearbyValue(correctAnswer, usedOptions);
        // 确保新生成的选项不重复且不与正确答案相同
        if (!usedOptions.contains(wrongOption) && !wrongOption.equals(formattedCorrectAnswer)) {
            options.add(wrongOption);
            usedOptions.add(wrongOption);
        }
    }

    return options;
}

/**
 * 格式化三角函数值
 */
private String formatTrigValue(double value) {
    // 对于特殊值进行精确表示
    if (Math.abs(value) < 1e-10) return "0"; // 接近0的值
    if (Math.abs(value - 1.0) < 1e-10) return "1";
    if (Math.abs(value + 1.0) < 1e-10) return "-1";
    if (Math.abs(value - 0.5) < 1e-10) return "0.5";
    if (Math.abs(value + 0.5) < 1e-10) return "-0.5";
    if (Math.abs(value - Math.sqrt(2)/2) < 1e-10) return "0.71"; // √2/2 ≈ 0.707
    if (Math.abs(value + Math.sqrt(2)/2) < 1e-10) return "-0.71";
    if (Math.abs(value - Math.sqrt(3)/2) < 1e-10) return "0.87"; // √3/2 ≈ 0.866
    if (Math.abs(value + Math.sqrt(3)/2) < 1e-10) return "-0.87";
    if (Math.abs(value - Math.sqrt(3)) < 1e-10) return "1.73"; // √3 ≈ 1.732
    if (Math.abs(value + Math.sqrt(3)) < 1e-10) return "-1.73";

    // 对于tan(90°)等未定义值
    if (Double.isInfinite(value) || Double.isNaN(value)) {
        return "undefined";
    }

    // 其他值保留两位小数
    return String.format("%.2f", value);
}

/**
 * 生成接近正确答案的选项
 */
private String generateNearbyValue(double correctAnswer, Set<String> usedOptions) {
    // 对于特殊值直接返回简单值
    if (Double.isInfinite(correctAnswer) || Double.isNaN(correctAnswer)) {
        return "0";
    }

    // 生成在正确答案附近的值
    double variation = (random.nextDouble() - 0.5) * 2; // -1 到 1 之间的随机数
    double wrongAnswer = correctAnswer + variation;

    // 格式化生成的值
    String formatted = formatTrigValue(wrongAnswer);

    // 确保不会生成与已使用选项相同的值，最多尝试10次
    int attempts = 0;
    while (usedOptions.contains(formatted) && attempts < 10) {
        variation = (random.nextDouble() - 0.5) * 2;
        wrongAnswer = correctAnswer + variation;
        formatted = formatTrigValue(wrongAnswer);
        attempts++;
    }

    return formatted;
}

/**
 * 计算三角函数
 */
private double calculateTrigFunction(String function, int angle) {
    double radians = Math.toRadians(angle);
    switch (function) {
        case "sin":
            // 对特定角度返回精确值
            switch (angle) {
                case 0: return 0;
                case 30: return 0.5;
                case 45: return Math.sqrt(2)/2;
                case 60: return Math.sqrt(3)/2;
                case 90: return 1;
                case 120: return Math.sqrt(3)/2;
                case 135: return Math.sqrt(2)/2;
                case 150: return 0.5;
                case 180: return 0;
                case 210: return -0.5;
                case 225: return -Math.sqrt(2)/2;
                case 270: return -1;
                case 300: return -Math.sqrt(3)/2;
                case 315: return -Math.sqrt(2)/2;
                case 330: return -0.5;
                default: return Math.sin(radians);
            }
        case "cos":
            // 对特定角度返回精确值
            switch (angle) {
                case 0: return 1;
                case 30: return Math.sqrt(3)/2;
                case 45: return Math.sqrt(2)/2;
                case 60: return 0.5;
                case 90: return 0;
                case 120: return -0.5;
                case 135: return -Math.sqrt(2)/2;
                case 150: return -Math.sqrt(3)/2;
                case 180: return -1;
                case 210: return -Math.sqrt(3)/2;
                case 225: return -Math.sqrt(2)/2;
                case 270: return 0;
                case 300: return 0.5;
                case 315: return Math.sqrt(2)/2;
                case 330: return Math.sqrt(3)/2;
                default: return Math.cos(radians);
            }
        case "tan":
            // 对特定角度返回精确值或未定义
            switch (angle) {
                case 0: return 0;
                case 30: return Math.sqrt(3)/3;
                case 45: return 1;
                case 60: return Math.sqrt(3);
                case 90: return Double.POSITIVE_INFINITY; // 未定义
                case 120: return -Math.sqrt(3);
                case 135: return -1;
                case 150: return -Math.sqrt(3)/3;
                case 180: return 0;
                case 210: return Math.sqrt(3)/3;
                case 225: return 1;
                case 270: return Double.POSITIVE_INFINITY; // 未定义
                case 300: return -Math.sqrt(3);
                case 315: return -1;
                case 330: return -Math.sqrt(3)/3;
                default: return Math.tan(radians);
            }
        default: return 0;
    }
}


    /**
     * 生成错误选项
     */
    private List<Integer> generateWrongOptions(int correctAnswer) {
        List<Integer> options = new ArrayList<>();
        Set<Integer> usedOptions = new HashSet<>();
        usedOptions.add(correctAnswer);

        while (options.size() < 3) {
            int wrongAnswer;
            if (correctAnswer == 0) {
                wrongAnswer = random.nextInt(20) - 10;
            } else {
                // 生成接近正确答案的错误选项
                int variation = random.nextInt(Math.max(1, Math.abs(correctAnswer) / 2)) + 1;
                wrongAnswer = correctAnswer + (random.nextBoolean() ? variation : -variation);
            }

            if (!usedOptions.contains(wrongAnswer)) {
                options.add(wrongAnswer);
                usedOptions.add(wrongAnswer);
            }
        }

        return options;
    }

    /**
     * 计算基本运算
     */
    private int calculate(int a, int b, String operation) {
        switch (operation) {
            case "+": return a + b;
            case "-": return a - b;
            case "*": return a * b;
            case "/": return b != 0 ? a / b : 0;
            default: return 0;
        }
    }


    /**
     * 生成复合运算表达式
     * @param operatorCount 运算符数量（1-3个）
     * @return 返回[表达式字符串, 计算结果字符串]
     */
    private String[] generateCompoundExpression(int operatorCount) {
        StringBuilder expression = new StringBuilder();
        List<Integer> operands = new ArrayList<>();
        List<String> operators = new ArrayList<>();
        
        // 生成操作数（运算符数量+1个操作数）
        for (int i = 0; i <= operatorCount; i++) {
            operands.add(MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE));
        }
        
        // 生成运算符
        String[] availableOps = {"+", "-", "*"};
        for (int i = 0; i < operatorCount; i++) {
            operators.add(availableOps[random.nextInt(availableOps.length)]);
        }
        
        // 构建表达式字符串
        expression.append(operands.get(0));
        for (int i = 0; i < operatorCount; i++) {
            expression.append(" ").append(operators.get(i)).append(" ").append(operands.get(i + 1));
        }
        expression.append(" = ?");
        
        // 计算表达式结果
        int result = calculateCompoundExpression(operands, operators);
        
        return new String[]{expression.toString(), String.valueOf(result)};
    }
    
    /**
     * 生成初中复合运算表达式（确保包含平方/开方）
     */
    private String[] generateJuniorCompoundExpressionWithGuarantee(int operatorCount) {
        StringBuilder expression = new StringBuilder();
        List<Integer> operands = new ArrayList<>();
        List<String> operators = new ArrayList<>();
        
        // 生成操作数（运算符数量+1个操作数）
        for (int i = 0; i <= operatorCount; i++) {
            operands.add(MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE));
        }
        
        // 确保至少有一个平方或开方运算
        boolean hasSquareOrRoot = false;
        
        // 生成运算符
        for (int i = 0; i < operatorCount; i++) {
            String[] availableOps;
            if (!hasSquareOrRoot && i == operatorCount - 1) {
                // 最后一个运算符必须是平方或开方
                availableOps = new String[]{"²", "√"};
                hasSquareOrRoot = true;
            } else if (!hasSquareOrRoot && random.nextDouble() < 0.4) {
                // 40%概率选择平方或开方
                availableOps = new String[]{"+", "-", "*", "/", "²", "√"};
            } else {
                // 其他情况选择基础运算
                availableOps = new String[]{"+", "-", "*", "/"};
            }
            
            String selectedOp = availableOps[random.nextInt(availableOps.length)];
            if (selectedOp.equals("²") || selectedOp.equals("√")) {
                hasSquareOrRoot = true;
            }
            operators.add(selectedOp);
        }
        
        // 构建表达式字符串
        expression.append(operands.get(0));
        for (int i = 0; i < operatorCount; i++) {
            if (operators.get(i).equals("²")) {
                expression.append("²");
            } else if (operators.get(i).equals("√")) {
                // 确保开方的是完全平方数
                int perfectSquare = (int) Math.pow(random.nextInt(10) + 1, 2);
                expression.append("√").append(perfectSquare);
                operands.set(i + 1, (int) Math.sqrt(perfectSquare));
            } else {
                expression.append(" ").append(operators.get(i)).append(" ").append(operands.get(i + 1));
            }
        }
        expression.append(" = ?");
        
        // 计算表达式结果
        int result = calculateJuniorCompoundExpression(operands, operators);
        
        return new String[]{expression.toString(), String.valueOf(result)};
    }

    /**
     * 生成初中复合运算表达式（包含平方/开方）
     */
    private String[] generateJuniorCompoundExpression(int operatorCount) {
        StringBuilder expression = new StringBuilder();
        List<Integer> operands = new ArrayList<>();
        List<String> operators = new ArrayList<>();
        
        // 生成操作数（运算符数量+1个操作数）
        for (int i = 0; i <= operatorCount; i++) {
            operands.add(MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE));
        }
        
        // 生成运算符（包含平方/开方）
        String[] availableOps = {"+", "-", "*", "/", "²", "√"};
        for (int i = 0; i < operatorCount; i++) {
            operators.add(availableOps[random.nextInt(availableOps.length)]);
        }
        
        // 构建表达式字符串
        expression.append(operands.get(0));
        for (int i = 0; i < operatorCount; i++) {
            if (operators.get(i).equals("²")) {
                expression.append("²");
            } else if (operators.get(i).equals("√")) {
                // 确保开方的是完全平方数
                int perfectSquare = (int) Math.pow(random.nextInt(10) + 1, 2);
                expression.append("√").append(perfectSquare);
                operands.set(i + 1, (int) Math.sqrt(perfectSquare));
            } else {
                expression.append(" ").append(operators.get(i)).append(" ").append(operands.get(i + 1));
            }
        }
        expression.append(" = ?");
        
        // 计算表达式结果
        int result = calculateJuniorCompoundExpression(operands, operators);
        
        return new String[]{expression.toString(), String.valueOf(result)};
    }

    /**
     * 生成包含除法的复合运算表达式
     */
    private String[] generateCompoundExpressionWithDivision(int operatorCount) {
        StringBuilder expression = new StringBuilder();
        List<Integer> operands = new ArrayList<>();
        List<String> operators = new ArrayList<>();
        
        // 生成操作数（运算符数量+1个操作数）
        for (int i = 0; i <= operatorCount; i++) {
            operands.add(MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE));
        }
        
        // 生成运算符（包含除法）
        String[] availableOps = {"+", "-", "*", "/"};
        for (int i = 0; i < operatorCount; i++) {
            operators.add(availableOps[random.nextInt(availableOps.length)]);
        }
        
        // 构建表达式字符串
        expression.append(operands.get(0));
        for (int i = 0; i < operatorCount; i++) {
            expression.append(" ").append(operators.get(i)).append(" ").append(operands.get(i + 1));
        }
        expression.append(" = ?");
        
        // 计算表达式结果
        int result = calculateCompoundExpressionWithDivision(operands, operators);
        
        return new String[]{expression.toString(), String.valueOf(result)};
    }
    
    /**
     * 计算复合表达式
     */
    private int calculateCompoundExpression(List<Integer> operands, List<String> operators) {
        // 先处理乘除法，再处理加减法
        List<Integer> numbers = new ArrayList<>(operands);
        List<String> ops = new ArrayList<>(operators);
        
        // 第一轮：处理乘除法
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("*")) {
                int result = numbers.get(i) * numbers.get(i + 1);
                numbers.set(i, result);
                numbers.remove(i + 1);
                ops.remove(i);
                i--; // 调整索引
            }
        }
        
        // 第二轮：处理加减法
        int result = numbers.get(0);
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("+")) {
                result += numbers.get(i + 1);
            } else if (ops.get(i).equals("-")) {
                result -= numbers.get(i + 1);
            }
        }
        
        return result;
    }
    
    /**
     * 生成高中复合运算表达式（确保包含三角函数）
     */
    private String[] generateSeniorCompoundExpressionWithGuarantee(int operatorCount) {
        StringBuilder expression = new StringBuilder();
        List<Double> operands = new ArrayList<>();
        List<String> operators = new ArrayList<>();
        
        // 生成操作数（运算符数量+1个操作数）
        for (int i = 0; i <= operatorCount; i++) {
            operands.add((double)(MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE)));
        }
        
        // 确保至少有一个三角函数运算
        boolean hasTrigFunction = false;
        
        // 生成运算符
        for (int i = 0; i < operatorCount; i++) {
            String[] availableOps;
            if (!hasTrigFunction && i == operatorCount - 1) {
                // 最后一个运算符必须是三角函数
                availableOps = new String[]{"sin", "cos", "tan"};
                hasTrigFunction = true;
            } else if (!hasTrigFunction && random.nextDouble() < 0.4) {
                // 40%概率选择三角函数
                availableOps = new String[]{"+", "-", "*", "/", "sin", "cos", "tan"};
            } else {
                // 其他情况选择基础运算
                availableOps = new String[]{"+", "-", "*", "/"};
            }
            
            String selectedOp = availableOps[random.nextInt(availableOps.length)];
            if (selectedOp.equals("sin") || selectedOp.equals("cos") || selectedOp.equals("tan")) {
                hasTrigFunction = true;
            }
            operators.add(selectedOp);
        }
        
        // 构建表达式字符串
        expression.append(operands.get(0).intValue());
        for (int i = 0; i < operatorCount; i++) {
            if (operators.get(i).equals("sin") || operators.get(i).equals("cos") || operators.get(i).equals("tan")) {
                // 生成常见角度
                int[] commonAngles = {0, 30, 45, 60, 90, 120, 135, 150, 180, 210, 225, 270, 300, 315, 330};
                int angle = commonAngles[random.nextInt(commonAngles.length)];
                expression.append(" ").append(operators.get(i)).append("(").append(angle).append("°)");
                
                // 计算三角函数值
                double trigValue = calculateTrigFunction(operators.get(i), angle);
                operands.set(i + 1, trigValue);
            } else {
                expression.append(" ").append(operators.get(i)).append(" ").append(operands.get(i + 1).intValue());
            }
        }
        expression.append(" = ?");
        
        // 计算表达式结果
        int result = calculateSeniorCompoundExpression(operands, operators);
        
        return new String[]{expression.toString(), String.valueOf(result)};
    }

    /**
     * 生成高中复合运算表达式（包含三角函数）
     */
    private String[] generateSeniorCompoundExpression(int operatorCount) {
        StringBuilder expression = new StringBuilder();
        List<Double> operands = new ArrayList<>();
        List<String> operators = new ArrayList<>();
        
        // 生成操作数（运算符数量+1个操作数）
        for (int i = 0; i <= operatorCount; i++) {
            operands.add((double)(MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE)));
        }
        
        // 生成运算符（包含三角函数）
        String[] availableOps = {"+", "-", "*", "/", "sin", "cos", "tan"};
        for (int i = 0; i < operatorCount; i++) {
            operators.add(availableOps[random.nextInt(availableOps.length)]);
        }
        
        // 构建表达式字符串
        expression.append(operands.get(0).intValue());
        for (int i = 0; i < operatorCount; i++) {
            if (operators.get(i).equals("sin") || operators.get(i).equals("cos") || operators.get(i).equals("tan")) {
                // 生成常见角度
                int[] commonAngles = {0, 30, 45, 60, 90, 120, 135, 150, 180, 210, 225, 270, 300, 315, 330};
                int angle = commonAngles[random.nextInt(commonAngles.length)];
                expression.append(" ").append(operators.get(i)).append("(").append(angle).append("°)");
                
                // 计算三角函数值
                double trigValue = calculateTrigFunction(operators.get(i), angle);
                operands.set(i + 1, trigValue);
            } else {
                expression.append(" ").append(operators.get(i)).append(" ").append(operands.get(i + 1).intValue());
            }
        }
        expression.append(" = ?");
        
        // 计算表达式结果
        int result = calculateSeniorCompoundExpression(operands, operators);
        
        return new String[]{expression.toString(), String.valueOf(result)};
    }

    /**
     * 生成高级复合运算表达式（包含平方运算）
     */
    private String[] generateAdvancedCompoundExpression(int operatorCount) {
        StringBuilder expression = new StringBuilder();
        List<Integer> operands = new ArrayList<>();
        List<String> operators = new ArrayList<>();
        
        // 生成操作数（运算符数量+1个操作数）
        for (int i = 0; i <= operatorCount; i++) {
            operands.add(MIN_OPERAND_VALUE + random.nextInt(MAX_OPERAND_VALUE));
        }
        
        // 生成运算符（包含平方运算）
        String[] availableOps = {"+", "-", "*", "/", "²"};
        for (int i = 0; i < operatorCount; i++) {
            operators.add(availableOps[random.nextInt(availableOps.length)]);
        }
        
        // 构建表达式字符串
        expression.append(operands.get(0));
        for (int i = 0; i < operatorCount; i++) {
            if (operators.get(i).equals("²")) {
                expression.append("²");
            } else {
                expression.append(" ").append(operators.get(i)).append(" ").append(operands.get(i + 1));
            }
        }
        expression.append(" = ?");
        
        // 计算表达式结果
        int result = calculateAdvancedCompoundExpression(operands, operators);
        
        return new String[]{expression.toString(), String.valueOf(result)};
    }
    
    /**
     * 计算包含除法的复合表达式
     */
    private int calculateCompoundExpressionWithDivision(List<Integer> operands, List<String> operators) {
        // 先处理乘除法，再处理加减法
        List<Integer> numbers = new ArrayList<>(operands);
        List<String> ops = new ArrayList<>(operators);
        
        // 第一轮：处理乘除法
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("*")) {
                int result = numbers.get(i) * numbers.get(i + 1);
                numbers.set(i, result);
                numbers.remove(i + 1);
                ops.remove(i);
                i--; // 调整索引
            } else if (ops.get(i).equals("/")) {
                if (numbers.get(i + 1) != 0) {
                    int result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                } else {
                    // 避免除零错误，重新生成
                    numbers.set(i + 1, 1 + random.nextInt(MAX_OPERAND_VALUE));
                    int result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                }
            }
        }
        
        // 第二轮：处理加减法
        int result = numbers.get(0);
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("+")) {
                result += numbers.get(i + 1);
            } else if (ops.get(i).equals("-")) {
                result -= numbers.get(i + 1);
            }
        }
        
        return result;
    }
    
    /**
     * 计算初中复合表达式（包含平方/开方）
     */
    private int calculateJuniorCompoundExpression(List<Integer> operands, List<String> operators) {
        // 先处理平方和开方运算
        List<Integer> numbers = new ArrayList<>(operands);
        List<String> ops = new ArrayList<>(operators);
        
        // 第一轮：处理平方和开方运算
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("²")) {
                int result = numbers.get(i) * numbers.get(i);
                numbers.set(i, result);
                ops.remove(i);
                i--; // 调整索引
            } else if (ops.get(i).equals("√")) {
                // 开方运算已经在生成时处理了
                ops.remove(i);
                i--; // 调整索引
            }
        }
        
        // 第二轮：处理乘除法
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("*")) {
                int result = numbers.get(i) * numbers.get(i + 1);
                numbers.set(i, result);
                numbers.remove(i + 1);
                ops.remove(i);
                i--; // 调整索引
            } else if (ops.get(i).equals("/")) {
                if (numbers.get(i + 1) != 0) {
                    int result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                } else {
                    // 避免除零错误，重新生成
                    numbers.set(i + 1, 1 + random.nextInt(MAX_OPERAND_VALUE));
                    int result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                }
            }
        }
        
        // 第三轮：处理加减法
        int result = numbers.get(0);
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("+")) {
                result += numbers.get(i + 1);
            } else if (ops.get(i).equals("-")) {
                result -= numbers.get(i + 1);
            }
        }
        
        return result;
    }

    /**
     * 计算高中复合表达式（包含三角函数）
     */
    private int calculateSeniorCompoundExpression(List<Double> operands, List<String> operators) {
        // 先处理三角函数运算
        List<Double> numbers = new ArrayList<>(operands);
        List<String> ops = new ArrayList<>(operators);
        
        // 第一轮：处理三角函数运算
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("sin") || ops.get(i).equals("cos") || ops.get(i).equals("tan")) {
                // 三角函数运算已经在生成时处理了
                ops.remove(i);
                i--; // 调整索引
            }
        }
        
        // 第二轮：处理乘除法
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("*")) {
                double result = numbers.get(i) * numbers.get(i + 1);
                numbers.set(i, result);
                numbers.remove(i + 1);
                ops.remove(i);
                i--; // 调整索引
            } else if (ops.get(i).equals("/")) {
                if (numbers.get(i + 1) != 0) {
                    double result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                } else {
                    // 避免除零错误，重新生成
                    numbers.set(i + 1, 1.0 + random.nextInt(MAX_OPERAND_VALUE));
                    double result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                }
            }
        }
        
        // 第三轮：处理加减法
        double result = numbers.get(0);
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("+")) {
                result += numbers.get(i + 1);
            } else if (ops.get(i).equals("-")) {
                result -= numbers.get(i + 1);
            }
        }
        
        return (int) Math.round(result);
    }

    /**
     * 计算高级复合表达式（包含平方运算）
     */
    private int calculateAdvancedCompoundExpression(List<Integer> operands, List<String> operators) {
        // 先处理平方运算
        List<Integer> numbers = new ArrayList<>(operands);
        List<String> ops = new ArrayList<>(operators);
        
        // 第一轮：处理平方运算
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("²")) {
                int result = numbers.get(i) * numbers.get(i);
                numbers.set(i, result);
                ops.remove(i);
                i--; // 调整索引
            }
        }
        
        // 第二轮：处理乘除法
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("*")) {
                int result = numbers.get(i) * numbers.get(i + 1);
                numbers.set(i, result);
                numbers.remove(i + 1);
                ops.remove(i);
                i--; // 调整索引
            } else if (ops.get(i).equals("/")) {
                if (numbers.get(i + 1) != 0) {
                    int result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                } else {
                    // 避免除零错误，重新生成
                    numbers.set(i + 1, 1 + random.nextInt(MAX_OPERAND_VALUE));
                    int result = numbers.get(i) / numbers.get(i + 1);
                    numbers.set(i, result);
                    numbers.remove(i + 1);
                    ops.remove(i);
                    i--; // 调整索引
                }
            }
        }
        
        // 第三轮：处理加减法
        int result = numbers.get(0);
        for (int i = 0; i < ops.size(); i++) {
            if (ops.get(i).equals("+")) {
                result += numbers.get(i + 1);
            } else if (ops.get(i).equals("-")) {
                result -= numbers.get(i + 1);
            }
        }
        
        return result;
    }

    /**
     * 获取随机运算符
     */
    private String getRandomOperation(String operations) {
        int index = random.nextInt(operations.length());
        return String.valueOf(operations.charAt(index));
    }

    /**
     * 难度级别枚举
     */
    public enum Level {
        小学, 初中, 高中
    }
}