锯齿状阵列的排列

时间:2011-07-20 15:49:38

标签: recursion vbscript asp-classic permutation jagged-arrays

我正在尝试在经典的asp(vbscript)中创建一个多维数组的排列,而我却被严重困住了。我已经尝试了我自己的几个函数,并尝试复制几个PHP版本,但我经常最终得到的东西要么进入缓冲区溢出/无限递归,要么我得到的结果更像是组合而不是排列,如果我理解正确的差异。

让我们说这是衬衫。衬衫可以有颜色,尺寸和款式。 (实际系统允许任意数量的“组”选项(想想颜色,大小等)以及每组中的任意数量的选项(每个特定大小,每种特定颜色等)。

例如:

small   med         lg      xl
red     blue        green   white
pocket  no-pocket

请注意,数组的任一维度中的元素数量都是事先未知的;此外,并非所有第二维都具有相同数量的元素。

我需要遍历每个可能包含每行选项的唯一选项。在这个特定的例子中,将有32个选项(因为我需要忽略任何给定选项具有空值的结果,因为asp并不像我期望的那样真正处理锯齿状数组。所以: 小红色口袋 小红色无口袋 小蓝口袋 小蓝色无口袋 等

一旦我完成了这个部分,我就需要将它与数据库中的一些ID集成,但我很确定我可以自己做这部分。这是让我失望的递归功能。

任何人都能指出我在一个良好的起点或帮助我吗?任何帮助都非常感谢!

3 个答案:

答案 0 :(得分:3)

20行的通用解决方案!

Function Permute(parameters)

    Dim results, parameter, count, i, j, k, modulus

    count = 1
    For Each parameter In parameters
        count = count * (UBound(parameter) + 1)
    Next

    results = Array()
    Redim results(count - 1)

    For i = 0 To count - 1
        j = i
        For Each parameter In parameters
            modulus = UBound(parameter) + 1
            k = j Mod modulus
            If Len(results(i)) > 0 Then _
                results(i) = results(i) & vbTab
            results(i) = results(i) & parameter(k)
            j = j \ modulus
        Next
    Next

    Permute = results

End Function

答案 1 :(得分:2)

为了避免术语问题:我写了一个小程序:

  Dim aaItems : aaItems = Array( _
      Array( "small", "med", "lg", "xl" ) _
    , Array( "red", "blue", "green", "white" ) _
    , Array( "pocket", "no-pocket" ) _
  )

  Dim oOdoDemo : Set oOdoDemo = New cOdoDemo.init( aaItems )
  oOdoDemo.run 33

这就是它的输出:

  0: small red pocket
  1: small red no-pocket
  2: small blue pocket
  3: small blue no-pocket
  4: small green pocket
  5: small green no-pocket
  6: small white pocket
  7: small white no-pocket
  8: med red pocket
  9: med red no-pocket
 10: med blue pocket
 11: med blue no-pocket
 12: med green pocket
 13: med green no-pocket
 14: med white pocket
 15: med white no-pocket
 16: lg red pocket
 17: lg red no-pocket
 18: lg blue pocket
 19: lg blue no-pocket
 20: lg green pocket
 21: lg green no-pocket
 22: lg white pocket
 23: lg white no-pocket
 24: xl red pocket
 25: xl red no-pocket
 26: xl blue pocket
 27: xl blue no-pocket
 28: xl green pocket
 29: xl green no-pocket
 30: xl white pocket
 31: xl white no-pocket
 32: small red pocket

如果这看起来像是问题解决方案的种子,那么就这样说,我将发布cOdoDemo类的代码。

cOdoDemo代码:

'' cOdoDemo - Q&D combinations generator (odometer approach)
'
' based on ideas from:
'  !! http://www.quickperm.org/index.php
'  !! http://www.ghettocode.net/perl/Buzzword_Generator
'  !! http://www.dreamincode.net/forums/topic/107837-vb6-combinatorics-lottery-problem/
'  !! http://stackoverflow.com/questions/127704/algorithm-to-return-all-combinations-of-k-elements-from-n
Class cOdoDemo

Private m_nPlaces    ' # of places/slots/digits/indices
Private m_nPlacesUB  ' UBound (for VBScript only)
Private m_aLasts     ' last index for each place => carry on
Private m_aDigits    ' the digits/indices to spin around

Private m_aaItems    ' init: AoA containing the elements to spin
Private m_aWords     ' one result: array of combined

Private m_nPos       ' current increment position

'' init( aaItems ) - use AoA of 'words' in positions to init the
''                   odometer
Public Function init( aaItems )
  Set init = Me
  m_aaItems   = aaItems
  m_nPlacesUB = UBound( m_aaItems )
  m_nPlaces   = m_nPlacesUB + 1
  ReDim m_aLasts(  m_nPlacesUB )
  ReDim m_aDigits( m_nPlacesUB )
  ReDim m_aWords(  m_nPlacesUB )
  Dim nRow
  For nRow = 0 To m_nPlacesUB
      Dim nCol
      For nCol = 0 To UBound( m_aaItems( nRow ) )
          m_aaItems( nRow )( nCol ) = m_aaItems( nRow )( nCol )
      Next
      m_aLasts( nRow ) = nCol - 1
  Next
  reset
End Function ' init

'' reset() - start afresh: all indices/digit set to 0 (=> first word), next
''           increment at utmost right
Public Sub reset()
  For m_nPos = 0 To m_nPlacesUB
      m_aDigits( m_nPos ) = 0
  Next
  m_nPos = m_nPlacesUB
End Sub ' reset

'' tick() - increment the current position and deal with carry
Public Sub tick()
  m_aDigits( m_nPos ) = m_aDigits( m_nPos ) + 1
  If m_aDigits( m_nPos ) > m_aLasts( m_nPos ) Then ' carry to left
     For m_nPos = m_nPos - 1 To 0 Step -1
         m_aDigits( m_nPos ) = m_aDigits( m_nPos ) + 1
         If m_aDigits( m_nPos ) <= m_aLasts( m_nPos ) Then ' carry done
            Exit For
         End If
     Next
     For m_nPos = m_nPos + 1 To m_nPlacesUB ' zero to right
         m_aDigits( m_nPos ) = 0
     Next
     m_nPos = m_nPlacesUB ' next increment at utmost right
  End If
End Sub ' tick

'' map() - build result array by getting the 'words' for the
''         indices in the current 'digits'
Private Sub map()
  Dim nIdx
  For nIdx = 0 To m_nPlacesUB
      m_aWords( nIdx ) = m_aaItems( nIdx )( m_aDigits( nIdx ) )
  Next
End Sub ' map

'' run( nMax ) - reset the odometer, tick/increment it nMax times and
''               display the mapped/translated result
Public Sub run( nMax )
  reset
  Dim oPad : Set oPad = New cPad.initWW( Len( CStr( nMax ) ) + 1, "L" )
  Dim nCnt
  For nCnt = 0 To nMax - 1
      map
      WScript.Echo oPad.pad( nCnt ) & ":", Join( m_aWords )
      tick
  Next
End Sub ' run

End Class ' cOdoDemo

一些提示/备注:想想一个里程表,它按照数字顺序生成6(7?)个位置/数字的所有组合。现在设想一个里程表,让你为每个地方/槽指定一个序列/有序的'数字'/单词/项目集。该规范由aaItems完成。

这是crp的代码,用于.run():

''= cPad - Q&D padding
Class cPad
Private m_nW
Private m_sW
Private m_sS
Private m_nW1
Public Function initWW( nW, sW )
  m_nW       = nW
  m_nW1      = m_nW + 1
  m_sW       = UCase( sW )
  m_sS       = Space( nW )
  Set initWW = Me
End Function
Public Function initWWC( nW, sW, sC )
  Set initWWC = initWW( nW, sW )
  m_sS        = String( nW, sC )
End Function
Public Function pad( vX )
  Dim sX : sX = CStr( vX )
  Dim nL : nL = Len( sX )
  If nL > m_nW Then
     Err.Raise 4711, "cPad::pad()", "too long: " & nL & " > " & m_nW
  End If
  Select Case m_sW
    Case "L"
      pad = Right( m_sS & sX, m_nW )
    Case "R"
      pad = Left( sX & m_sS, m_nW )
    Case "C"
      pad = Mid( m_sS & sX & m_sS, m_nW1 - ((m_nW1 - nL) \ 2), m_nW )
    Case Else
      Err.Raise 4711, "cPad::pad() Unknown m_sW: '" & m_sW & "'"
  End Select
End Function
End Class ' cPad

抱歉缺少文档。我会尽力回答你的所有问题。

答案 2 :(得分:0)

如果您只需要担心这四个固定类别,只需使用嵌套for循环。

如果类别数量可能会发生变化,则很容易定义递归解决方案:

  permute(index, permutation[1..n], sources[1..n])
  1. if index > n then print(permutation)
  2. else then
  3     for i = 1 to sources[index].length do
  4.       permutation[index] = sources[index][i]
  5.       permute(index+1, permutation, sources)

使用index = 0调用并置换为空以获得最佳结果(sources是包含类别的数组数组)。

示例:

  index = 1
  sources = [[blue, red, green], [small, medium, large], [wool, cotton, NULL], [shirt, NULL, NULL]].
  permutation = [NULL, NULL, NULL, NULL]

  permute(index, permutation, sources)
   note: n = 4 because that's how many categories there are
   index > n is false, so...
   compute length of sources[1]:
    sources[1][1] isn't NULL, so...
    sources[1][2] isn't NULL, so...
    sources[1][3] isn't NULL, so...
    sources[1].length = 3

   let i = 1... then permutation[1] = sources[1][1] = blue
   permute(2, permutation, sources)

   etc.