relentless/HighSchoolQuestionStrategy.java

import java.util.Random;

public class HighSchoolQuestionStrategy implements QuestionStrategy {
    private final Random random = new Random();
    private final String[] basicOps = {"+", "-", "*", "/"};
    private final String[] trigFuncs = {"sin", "cos", "tan"};

    @Override
    public String generateQuestion() {
        // 随机操作数个数 2-5
        int operandsCount = random.nextInt(4) + 2;
        StringBuilder sb = new StringBuilder();
        boolean hasTrig = false;

        for (int i = 0; i < operandsCount; i++) {
            int num = random.nextInt(100) + 1;

            // 每个操作数有概率加三角函数
            if (random.nextBoolean()) {
                String func = trigFuncs[random.nextInt(trigFuncs.length)];
                sb.append(func).append("(").append(num).append(")");
                hasTrig = true;
            } else {
                sb.append(num);
            }

            if (i != operandsCount - 1) {
                String op = basicOps[random.nextInt(basicOps.length)];
                sb.append(" ").append(op).append(" ");
            }
        }

        // 确保至少一个三角函数
        if (!hasTrig) {
            String func = trigFuncs[random.nextInt(trigFuncs.length)];
            int num = random.nextInt(100) + 1;
            return func + "(" + num + ") + " + sb.toString();
        }

        return sb.toString();
    }
}