Cálculo porcentaje de similitud entre Strings

C#: Calculating Percentage Similarity of 2 strings

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)));

}

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];

}