Our Permutation code in Visual Basic.
Permutation Class File:
Public Class Permutation
Inherits Combination
Private local_store
Protected perm_store
Private index As Integer
' till the ground for shuffle to grind on
Public Function possibleWordPermutations(candidates As List(Of String), size As Integer) As List(Of String())
perm_store = New List(Of String())
possibleWordCombinations(candidates, size)
' illegal 'r' value
If comb_store.Count = 0 Or r = 1 Then
perm_store = comb_store
Else
Dim last_two
last_two = New List(Of String())({New String() {"", ""}, New String() {"", ""}})
For i As Integer = 0 To comb_store.Count - 1
index = r - 1
' copy up last two elements of 'comb_store(i)'
last_two(0)(0) = comb_store(i)(index)
last_two(1)(1) = last_two(0)(0)
index -= 1
last_two(0)(1) = comb_store(i)(index)
last_two(1)(0) = last_two(0)(1)
index -= 1
local_store = New List(Of String())
local_store.Add(last_two(0))
local_store.Add(last_two(1))
If r > 2 Then
shuffleWord(local_store, i)
End If
perm_store.AddRange(local_store)
Next i
End If
Return perm_store
End Function
Private Sub shuffleWord(arg_store As List(Of String()), i As Integer)
local_store = New List(Of String())
Dim members
For j As Integer = 0 To arg_store.Count - 1
members = New List(Of String)
members.AddRange(arg_store(j))
' add 'index' 'comb_store(i)' element to this list of members
members.Add(comb_store(i)(index))
Dim temp_char As String
Dim shift_index As Integer = members.Count
' shuffle this pack of words
Do While shift_index > 0
' skip if already in store
If local_store.Contains(members.ToArray()) = False Then
local_store.Add(members.ToArray())
End If
' interchange these two neighbours
shift_index -= 1
If shift_index > 0 Then
temp_char = members(shift_index)
members(shift_index) = members(shift_index - 1)
members(shift_index - 1) = temp_char
End If
Loop
Next j
' Are there any elements left? repeat if yes
If index > 0 Then
index -= 1
shuffleWord(local_store, i)
End If
End Sub
End ClassMain Class:
Module Miscellaneous_Permutation
Sub Main()
Dim goods
goods = New List(Of String)(New String() {"Eno", "Chidi", "Olu", "Ahmed", "Osas", "Gbeda"})
Dim perm As New Permutation
Dim result As List(Of String()) = perm.possibleWordPermutations(goods, 3)
' print choices and operation
Console.Write("[ ")
For Each choice As String In perm.words
Console.Write(choice & "; ")
Next
Console.WriteLine("] permutation " & perm.r & ":" & Environment.NewLine)
' print out permutations nicely
Dim i = 0
For Each group As String() In result
i += 1
Console.Write(i & ": ")
For Each member As String In group
Console.Write(member & "; ")
Next
Console.WriteLine()
Next
Console.WriteLine(Environment.NewLine & "Number of ways is " & result.Count & ".")
End Sub
End ModuleTry it out!
Elegance (0.0)
