问字符串组合

EN

Public Sub test()

    Dim myAnimals As String = "cat dog horse ape hen mouse"

    Dim myAnimalCombinations As String() = BuildCombinations(myAnimals)

    For Each combination As String In myAnimalCombinations
        'Look on the Output Tab for the results!
        Console.WriteLine("(" & combination & ")")  
    Next combination


End Sub



Public Function BuildCombinations(ByVal inputString As String) As String()

    'Separate the sentence into useable words.
    Dim wordsArray As String() = inputString.Split(" ".ToCharArray)

    'A plase to store the results as we build them
    Dim returnArray() As String = New String() {""}

    'The 'combination level' that we're up to
    Dim wordDistance As Integer = 1

    'Go through all the combination levels...
    For wordDistance = 1 To wordsArray.GetUpperBound(0)

        'Go through all the words at this combination level...
        For wordIndex As Integer = 0 To wordsArray.GetUpperBound(0) - wordDistance

            'Get the first word of this combination level
            Dim combination As New System.Text.StringBuilder(wordsArray(wordIndex))

            'And all all the remaining words a this combination level
            For combinationIndex As Integer = 1 To wordDistance

                combination.Append(" " & wordsArray(wordIndex + combinationIndex))

            Next combinationIndex

            'Add this combination to the results
            returnArray(returnArray.GetUpperBound(0)) = combination.ToString

            'Add a new row to the results, ready for the next combination
            ReDim Preserve returnArray(returnArray.GetUpperBound(0) + 1)

        Next wordIndex

    Next wordDistance

    'Get rid of the last, blank row.
    ReDim Preserve returnArray(returnArray.GetUpperBound(0) - 1)

    'Return combinations to the calling method.
    Return returnArray

End Function

    Dim myAnimals As New StringBulder 
    myAnimals.Append("dog cat ... animal49 animal50") 
    myAnimals.Append(" ") 
    myAnimals.Append("animal51 ... animal99") 
    myAnimals.Append(" ") 
    myAnimals.Append("animal100 ... animal150") 

Dim myAnimalCombinations As String() = BuildCombinations(myAnimals.ToString)

for i = 0; i < arr.size; i++)
  for j = i; j < arr.size; j++)
    print i,j;