Compare two strings with numbers as words

Question

I have been given numbers as words:

{"one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten"};

Numbers are only up-to 10. And I my task is to compare given two input strings to each other.

It should basically work as you compare two numbers:

compare(1, 1) -> 0;
compare(1, 3) -> 1 < 3 as -1;
compare(5, 2) -> 5 > 2 as 1;

What would be the best suitable way to compare two strings like this?

Result would look something like this:

compare("one", "one") -> 0;
compare("one", "three") -> -1;
compare("five", "two") -> 1;

public int compare(String a, String b) {
    return 0;
}

Answer 1

You can use a map to code the Strings and their values. The benefit of this approach is that it has O(1) complexity as oppose to use of an array for instance.

Map<String, Integer> map = Map.of("one", 1, "two", 2, ...);

public int compare(String a, String b) {
      return Integer.compare(map.get(a),map.get(b));    
}

Full example:

public class Example {

    private final static Map<String, Integer> STRING_VALUE =
            Map.of("one", 1, "two", 2, "three", 3, "four", 4, "five", 5,
                    "six", 6, "seven", 7, "eight", 8, "nine", 9, "ten", 10);

    public static int compare(String a, String b) {
        return Integer.compare(STRING_VALUE.get(a),STRING_VALUE.get(b));
    }

   public static void main(String[] args) {
       System.out.println(compare("one", "one"));
       System.out.println(compare("one", "three"));
       System.out.println(compare("five", "two"));
    }
}

Output:

0
-1
1

Another solution is to use an ENUM:

Full Example:

public class Example {

    enum Values {
        ONE,
        TWO,
        THREE,
        FOUR,
        FIVE,
        SIX,
        SEVEN,
        EIGHT,
        NINE,
        TEN;
    }
    public static int compare(String a, String b) {
        Values vA = Values.valueOf(a.toUpperCase());
        Values vB = Values.valueOf(b.toUpperCase());
        return Integer.compare(vA.compareTo(vB), 0);
    }

   public static void main(String[] args) {
       System.out.println(compare("one", "one"));
       System.out.println(compare("one", "three"));
       System.out.println(compare("five", "two"));
    }
}

Output:

0
-1
1

Answer 2

Here is yet another way.

String s = "onetwothreefourfivesixseveneightnineten";
int compare(String a, String b) {
    return Integer.compare(s.indexOf(a),s.indexOf(b));
}