using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(CalculateSimilarity("Java", "Java"));

    }

    static int ComputeLevenshteinDistance(string source, string target)

    {

        if ((source == null) || (target == null)) return 0;

        if ((source.Length == 0) || (target.Length == 0)) return 0;

        if (source == target) return source.Length;

​

        int sourceWordCount = source.Length;

        int targetWordCount = target.Length;

​

        // Step 1

        if (sourceWordCount == 0)

            return targetWordCount;

​

        if (targetWordCount == 0)

            return sourceWordCount;

​

        int[,] distance = new int[sourceWordCount + 1, targetWordCount + 1];

​

        // Step 2

        for (int i = 0; i <= sourceWordCount; distance[i, 0] = i++);

        for (int j = 0; j <= targetWordCount; distance[0, j] = j++);

​

        for (int i = 1; i <= sourceWordCount; i++)

        {

            for (int j = 1; j <= targetWordCount; j++)

            {

                // Step 3

                int cost = (target[j - 1] == source[i - 1]) ? 0 : 1;

​

                // Step 4

                distance[i, j] = Math.Min(Math.Min(distance[i - 1, j] + 1, distance[i, j - 1] + 1), distance[i - 1, j - 1] + cost);

            }

        }

​

        return distance[sourceWordCount, targetWordCount];

    }

    static double CalculateSimilarity(string source, string target)

    {

        if ((source == null) || (target == null)) return 0.0;

        if ((source.Length == 0) || (target.Length == 0)) return 0.0;

        if (source == target) return 1.0;

​

        int stepsToSame = ComputeLevenshteinDistance(source, target);

        return (1.0 - ((double)stepsToSame / (double)Math.Max(source.Length, target.Length)));

    }

}