Task: Levenshtein distance



C#: using System;

namespace LevenshteinDistance
{
    class Program
    {
        static int LevenshteinDistance(string s, string t)
        {
            int n = s.Length;
            int m = t.Length;
            int[,] d = new int[n + 1, m + 1];
		
	    if (n == 0)
	    {
		return m;
	    }
	
	    if (m == 0)
	    {
		return n;
	    }

            for (int i = 0; i <= n; i++)
                d[i, 0] = i;
            for (int j = 0; j <= m; j++)
                d[0, j] = j;
			
            for (int j = 1; j <= m; j++)
                for (int i = 1; i <= n; i++)
                    if (s[i - 1] == t[j - 1])
                        d[i, j] = d[i - 1, j - 1];  
                    else
                        d[i, j] = Math.Min(Math.Min(
                            d[i - 1, j] + 1,    
                            d[i, j - 1] + 1),   
                            d[i - 1, j - 1] + 1 
                            );
            return d[n, m];
        }

        static void Main(string[] args)
        {
            if (args.Length == 2)
                Console.WriteLine("{0} -> {1} = {2}",
                    args[0], args[1], LevenshteinDistance(args[0], args[1]));
            else
                Console.WriteLine("Usage:-\n\nLevenshteinDistance <string1> <string2>");
        }
    }
}







COBOL:        identification division.
       program-id. Levenshtein.
 
       environment division.
       configuration section.
       repository.
           function all intrinsic.
 
       data division.
       working-storage section.
       77  string-a               pic x(255).
       77  string-b               pic x(255).
       77  length-a               pic 9(3).
       77  length-b               pic 9(3).
       77  distance               pic z(3).
       77  i                      pic 9(3).
       77  j                      pic 9(3).
       01  tab.
           05 filler              occurs 256.
              10 filler           occurs 256.
                 15 costs         pic 9(3).

       procedure division.
       main.
           move "kitten" to string-a
           move "sitting" to string-b
           perform levenshtein-dist

           move "rosettacode" to string-a
           move "raisethysword" to string-b
           perform levenshtein-dist
           stop run
           .
       levenshtein-dist.
           move length(trim(string-a)) to length-a
           move length(trim(string-b)) to length-b

           initialize tab
           
           perform varying i from 0 by 1 until i > length-a
              move i to costs(i + 1, 1)
           end-perform

           perform varying j from 0 by 1 until j > length-b
              move j to costs(1, j + 1)
           end-perform
           
           perform with test after varying i from 2 by 1 until i > length-a
              perform with test after varying j from 2 by 1 until j > length-b
                 if string-a(i - 1:1) = string-b(j - 1:1)
                    move costs(i - 1, j - 1) to costs(i, j)
                 else
                    move min(min(costs(i - 1, j) + 1,     
                                 costs(i, j - 1) + 1),    
                             costs(i - 1, j - 1) + 1)     
                       to costs(i, j)
                 end-if
              end-perform
           end-perform
           move costs(length-a + 1, length-b + 1) to distance
           display trim(string-a) " -> " trim(string-b) " = " trim(distance)
           .