算法问题

Question

论坛的技术文档那里就有一个阿

Answer 1

大部分都能正确算出来，TextBox有四个，分别输入四个要计算的数字：Option ExplicitConst PRECISION = 0.000001
Const COUNT_OF_NUMBER = 4
Const NUMBER_TO_BE_CAL = 24
Dim number(COUNT_OF_NUMBER) As Double
Dim expression(COUNT_OF_NUMBER) As StringFunction Search(n As Integer) As Boolean
    If n = 1 Then
        If Abs(number(0) - NUMBER_TO_BE_CAL) < PRECISION Then
            Label1.Caption = expression(0)
            Search = True
            Exit Function
        Else
            Search = False
            Exit Function
        End If
    End If
    
    Dim i As Integer, j As Integer
    For i = 0 To n - 1
        For j = i + 1 To n - 1
            Dim a As Double, b As Double
            Dim expa As String, expb As String
            
            a = number(i)
            b = number(j)
            number(j) = number(n - 1)
            
            expa = expression(i)
            expb = expression(j)
            expression(j) = expression(n - 1)
            
            expression(i) = "(" + expa + "+" + expb + ")"
            number(i) = a + b
            If Search(n - 1) Then
                Search = True
                Exit Function
            End If
            
            expression(i) = "(" + expa + "-" + expb + ")"
            number(i) = a - b
            If Search(n - 1) Then
                Search = True
                Exit Function
            End If
            
            expression(i) = "(" + expa + "-" + expb + ")"
            number(i) = b - a
            If Search(n - 1) Then
                Search = True
                Exit Function
            End If
            
            expression(i) = "(" + expa + "*" + expb + ")"
            number(i) = a * b
            If Search(n - 1) Then
                Search = True
                Exit Function
            End If
            
            If b <> 0 Then
                expression(i) = "(" + expa + "/" + expb + ")"
                number(i) = a / b
                If Search(n - 1) Then
                    Search = True
                    Exit Function
                End If
            End If
            
            If a <> 0 Then
                expression(i) = "(" + expa + "/" + expb + ")"
                number(i) = b / a
                If Search(n - 1) Then
                    Search = True
                    Exit Function
                End If
            End If
            
            number(i) = a
            number(j) = b
            expression(i) = expa
            expression(j) = expb
        Next j
    Next i
    Search = False
End FunctionPrivate Sub Command1_Click()
    Dim i As Integer
    For i = 0 To COUNT_OF_NUMBER - 1
        number(i) = Text1(i).Text
        expression(i) = Text1(i).Text
    Next i
    
    If Search(COUNT_OF_NUMBER) Then
        Label2.Caption = "计算成功！"
    Else
        Label2.Caption = "计算失败！"
        Label1.Caption = ""
    End If
End SubPrivate Sub Text1_GotFocus(Index As Integer)
    Text1(Index).SelStart = 0
    Text1(Index).SelLength = Len(Text1(Index))
End Sub