以下是引用xl在2017/12/18 10:46:00的发言：
编译出错提示：未申明名称： “PermutationAndCombination”
Dim lst_Permutation As List(Of String()) = PermutationAndCombination(Of String).GetPermutation(ary, ary.Length)
照抄8楼代码，全局代码
Public Class PermutationAndCombination(Of T)
''' <summary>
''' 交换两个变量
''' </summary>
''' <param name="a">变量1</param>
''' <param name="b">变量2</param>
Public Shared Sub Swap(ByRef a As T, ByRef b As T)
Dim temp As T = a
a = b
b = temp
End Sub
''' <summary>
''' 递归算法求数组的组合(私有成员)
''' </summary>
''' <param name="list">返回的范型</param>
''' <param name="t">所求数组</param>
''' <param name="n">辅助变量</param>
''' <param name="m">辅助变量</param>
''' <param name="b">辅助数组</param>
''' <param name="M">辅助变量M</param>
Private Shared Sub GetCombination(ByRef list As List(Of T()), t As T(), n As Integer, m__1 As Integer, b As Integer(), M__2 As Integer)
For i As Integer = n To m__1 Step -1
b(m__1 - 1) = i - 1
If m__1 > 1 Then
GetCombination(list, t, i - 1, m__1 - 1, b, M__2)
Else
If list Is Nothing Then
list = New List(Of T())()
End If
Dim temp As T() = New T(M__2 - 1) {}
For j As Integer = 0 To b.Length - 1
temp(j) = t(b(j))
Next
list.Add(temp)
End If
Next
End Sub
''' <summary>
''' 递归算法求排列(私有成员)
''' </summary>
''' <param name="list">返回的列表</param>
''' <param name="t">所求数组</param>
''' <param name="startIndex">起始标号</param>
''' <param name="endIndex">结束标号</param>
Private Shared Sub GetPermutation(ByRef list As List(Of T()), t As T(), startIndex As Integer, endIndex As Integer)
If startIndex = endIndex Then
If list Is Nothing Then
list = New List(Of T())()
End If
Dim temp As T() = New T(t.Length - 1) {}
t.CopyTo(temp, 0)
list.Add(temp)
Else
For i As Integer = startIndex To endIndex
Swap(t(startIndex), t(i))
GetPermutation(list, t, startIndex + 1, endIndex)
Swap(t(startIndex), t(i))
Next
End If
End Sub
''' <summary>
''' 求从起始标号到结束标号的排列，其余元素不变
''' </summary>
''' <param name="t">所求数组</param>
''' <param name="startIndex">起始标号</param>
''' <param name="endIndex">结束标号</param>
''' <returns>从起始标号到结束标号排列的范型</returns>
Public Shared Function GetPermutation(t As T(), startIndex As Integer, endIndex As Integer) As List(Of T())
If startIndex < 0 OrElse endIndex > t.Length - 1 Then
Return Nothing
End If
Dim list As New List(Of T())()
GetPermutation(list, t, startIndex, endIndex)
Return list
End Function
''' <summary>
''' 返回数组所有元素的全排列
''' </summary>
''' <param name="t">所求数组</param>
''' <returns>全排列的范型</returns>
Public Shared Function GetPermutation(t As T()) As List(Of T())
Return GetPermutation(t, 0, t.Length - 1)
End Function
''' <summary>
''' 求数组中n个元素的排列
''' </summary>
''' <param name="t">所求数组</param>
''' <param name="n">元素个数</param>
''' <returns>数组中n个元素的排列</returns>
Public Shared Function GetPermutation(t As T(), n As Integer) As List(Of T())
If n > t.Length Then
Return Nothing
End If
Dim list As New List(Of T())()
Dim c As List(Of T()) = GetCombination(t, n)
For i As Integer = 0 To c.Count - 1
Dim l As New List(Of T())()
GetPermutation(l, c(i), 0, n - 1)
list.AddRange(l)
Next
Return list
End Function
''' <summary>
''' 求数组中n个元素的组合
''' </summary>
''' <param name="t">所求数组</param>
''' <param name="n">元素个数</param>
''' <returns>数组中n个元素的组合的范型</returns>
Public Shared Function GetCombination(t As T(), n As Integer) As List(Of T())
If t.Length < n Then
Return Nothing
End If
Dim temp As Integer() = New Integer(n - 1) {}
Dim List As New List(Of T())()
GetCombination(List, t, t.Length, n, temp, n)
Return List
End Function
End Class
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Post By：2017/12/11 18:45:00 [显示全部帖子]
