Longest common substring - Code Snippets - Wikibooks

Longest common substring - Code Snippets - Wikibooks

Public Function LongestCommonSubstring(ByVal s1 As String, ByVal s2 As String) As Integer
     Dim num(s1.Length - 1, s2.Length - 1) As Integer   '2D array
     Dim letter1 As Char = Nothing
     Dim letter2 As Char = Nothing
     Dim len As Integer = 0
     Dim ans As Integer = 0
     For i As Integer = 0 To s1.Length - 1
         For j As Integer = 0 To s2.Length - 1
             letter1 = s1.Chars(i)
             letter2 = s2.Chars(j)
             If Not letter1.Equals(letter2) Then
                 num(i, j) = 0
             Else
                 If i.Equals(0) Or j.Equals(0) Then
                     num(i, j) = 1
                 Else
                     num(i, j) = 1 + num(i - 1, j - 1)
                 End If
                 If num(i, j) > len Then
                     len = num(i, j)
                     ans = num(i, j)
                 End If
             End If
         Next j
     Next i
     Return ans
 End Function