public class JuniorGenerator extends AbstractQuestionGenerator{
    public JuniorGenerator() {
        super(Level.JUNIOR);
    }

    @Override
    String generateExpression() {
        return generateSub(4);
    }

    private String generateSub(int depth) {
        if (depth == 0 || random.nextDouble() < 0.4) {
            return String.valueOf(getRandomNumber());
        }
        double r = random.nextDouble();
        if (r < 0.5) {
            String left = generateSub(depth - 1);
            String op = getRandomBinaryOp();
            String right = generateSub(depth - 1);
            return "(" + left + op + right + ")";
        } else if (r < 0.75) {
            String sub = generateSub(depth - 1);
            return "sqrt(" + sub + ")";
        } else {
            String sub = generateSub(depth - 1);
            return "(" + sub + ")^2";
        }
    }

    @Override
    boolean isValidForLevel(String expression) {
        return expression.contains("sqrt") || expression.contains("^2");
    }
}