String Levenshtein Distance - CSharp System

CSharp examples for System:String Algorithm

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Description

String Levenshtein Distance

Demo Code


using System.Linq;
using System.Collections.Generic;
using System;//from   w  w w.j  a  v a2s  .  c o  m

public class Main{
        public static int LevenshteinDistance(this string source, string match)
		{
			//TODO: Create levenstein automaton support
			int sourceLength = source.Length;
			int matchLength = match.Length;
			int[,] distances = new int[sourceLength + 1, matchLength + 1];

			// Step 1
			if (sourceLength == 0)
			{
				return matchLength;
			}

			if (matchLength == 0)
			{
				return sourceLength;
			}

			// Step 2
			for (int i = 0; i <= sourceLength; distances[i, 0] = i++)
			{
			}

			for (int j = 0; j <= matchLength; distances[0, j] = j++)
			{
			}

			// Step 3
			for (int i = 1; i <= sourceLength; i++)
			{
				//Step 4
				for (int j = 1; j <= matchLength; j++)
				{
					// Step 5
					int cost = (match[j - 1] == source[i - 1]) ? 0 : 1;

					// Step 6
					distances[i, j] = Math.Min(
						Math.Min(distances[i - 1, j] + 1, distances[i, j - 1] + 1),
						distances[i - 1, j - 1] + cost);
				}
			}
			// Step 7
			return distances[sourceLength, matchLength];
		}
}

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