Method isValid

ConstructSmallestNumberFromDIString.java:34–36

(int lastDigit, int currentDigit, char condition)

    }

    private boolean isValid(int lastDigit, int currentDigit, char condition) {
        return (condition == 'I' && lastDigit < currentDigit) || (condition == 'D' && lastDigit > currentDigit);
    }
}