10.11

package com;
import java.util.*;


public class test {
    private static final String[] OPERATORS = {"+", "-", "*", "/"};
    private static final int MIN_VALUE = 1;
    private static final int MAX_VALUE = 50;
    private static final Set<String> generatedQuestions = new HashSet<>();

    public static void main(String[] args) {
        generateQuestions(50);
    }

    public static void generateQuestions(int count) {
        for (int i = 0; i < count; i++) {
            String question = generateQuestion();
            while (generatedQuestions.contains(question)) {
                question = generateQuestion();
            }
            generatedQuestions.add(question);
            System.out.println(question);
        }
    }

    private static String generateQuestion() {
        Random random = new Random();
        int num1 = random.nextInt(MAX_VALUE - MIN_VALUE) + MIN_VALUE;
        int num2 = random.nextInt(MAX_VALUE - MIN_VALUE) + MIN_VALUE;
        String operator = OPERATORS[random.nextInt(OPERATORS.length)];
        return num1 + " " + operator + " " + num2;
    }
}