using System;

class Sample {
  private static int Min(int x, int y, int z)
  {
    return Math.Min(Math.Min(x, y), z);
  }

  private static int ComputeLevenshteinDistance(string strX, string strY)
  {
    if (strX == null)
      throw new ArgumentNullException("strX");
    if (strY == null)
      throw new ArgumentNullException("strY");

    if (strX.Length == 0)
      return strY.Length;
    if (strY.Length == 0)
      return strX.Length;

    var d = new int[strX.Length + 1, strY.Length + 1];

    for (var i = 0; i <= strX.Length; i++) {
      d[i, 0] = i;
    }

    for (var j = 0; j <= strY.Length; j++) {
      d[0, j] = j;
    }

    for (var j = 1; j <= strY.Length; j++) {
      for (var i = 1; i <= strX.Length; i++) {
        if (strX[i - 1] == strY[j - 1])
          d[i, j] = d[i - 1, j - 1];
        else
          d[i, j] = Min(d[i - 1, j] + 1,
                        d[i, j - 1] + 1,
                        d[i - 1, j - 1] + 1);
      }
    }

    return d[strX.Length, strY.Length];
  }

  static void Main()
  {
    foreach (var texts in new[] {
      new[] {"kitten", "sitting"},
      new[] {"Saturday", "Sunday"},
      new[] {"", "foo"},
      new[] {"にほんご", "にっぽんご"},
    }) {
      Console.WriteLine("{0} => {1} : {2}",
                        texts[0],
                        texts[1],
                        ComputeLevenshteinDistance(texts[0], texts[1]));
    }
  }
}

Imports System

Class Sample
  Private Shared Function Min(ByVal x As Integer, ByVal y As Integer, ByVal z As Integer) As Integer
    Return Math.Min(Math.Min(x, y), z)
  End Function

  Private Shared Function ComputeLevenshteinDistance(ByVal strX As String, ByVal strY As String) As Integer
    If strX Is Nothing Then Throw New ArgumentNullException("strX")
    If strY Is Nothing Then Throw New ArgumentNullException("strY")

    If strX.Length = 0 Then Return strY.Length
    If strY.Length = 0 Then Return strX.Length

    Dim d(strX.Length + 1, strY.Length + 1) As Integer

    For i As Integer = 0 To strX.Length
      d(i, 0) = i
    Next

    For j As Integer = 0 To strY.Length
      d(0, j) = j
    Next

    For j As Integer = 1 To strY.Length
      For i As Integer = 1 To strX.Length
        If strX(i - 1) = strY(j - 1) Then
          d(i, j) = d(i - 1, j - 1)
        Else
          d(i, j) = Min(d(i - 1, j) + 1, d(i, j - 1) + 1, d(i - 1, j - 1) + 1)
        End If
      Next
    Next

    Return d(strX.Length, strY.Length)
  End Function

  Shared Sub Main()
    For Each texts As String() In New String()() { _
      New String() {"kitten", "sitting"}, _
      New String() {"Saturday", "Sunday"}, _
      New String() {"", "foo"}, _
      New String() {"にほんご", "にっぽんご"} _
    }
      Console.WriteLine("{0} => {1} : {2}", _
                        texts(0), _
                        texts(1), _
                        ComputeLevenshteinDistance(texts(0), texts(1)))
    Next
  End Sub
End Class