编程题目（分割铅块）

海狸先生

有一40千克的铅块，把它分成4块（每块为整数重量），用这4块铅块作为天平称的砝码，可以称出1----40千克任何重量（整数重量）的物体，问：如何分割？

注意：

1.天平两边都可以放砝码。

2.以上所有的数值均为整数，而不是小数。

3.一次性称出重量，而不能分步称出，然后求其总和。

tmtony

我有些晕

Trynew

Public Sub Test()

Dim a As Integer, b As Integer, c As Integer, d As Integer, i As Integer

For a = 1 To 40: For b = a To 40: For c = b To 40: For d = c To 40

  If a + b + c + d = 40 Then

    For i = 1 To 39

        If CheckNum(i, a, b, c, d) = False Then Exit For

    Next

    If i = 40 Then Debug.Print a & "," & b & "," & c & "," & d

  End If

Next: Next: Next: Next

End SubPublic Function CheckNum(Num As Integer, w As Integer, x As Integer, y As Integer, z As Integer) As Boolean

For a = -1 To 1: For b = -1 To 1: For c = -1 To 1: For d = -1 To 1

  If a * w + b * x + c * y + d * z = Num Then

    CheckNum = True

    Exit Function

  End If

Next: Next: Next: Next

End Function

答案是：1,3,9,27（跟我用心算的结果一样，并且是唯一解 :）

海狸先生

可以简化一下a肯定等于1，d 肯定等于　40-1-b-cPublic Sub Test()

Dim b As Integer, c As Integer, i As Integer

For b = 1 To 37

   For c = b To 37

      For i = 1 To 39

         If CheckNum(i, b, c) = False Then Exit For

      Next

      If i = 40 Then Debug.Print "1," & b & "," & c & "," & 40 - 1 - b - c

   Next

Next

End SubPublic Function CheckNum(Num As Integer, x As Integer, y As Integer) As Boolean

For a = -1 To 1

   For b = -1 To 1

      For c = -1 To 1

         For d = -1 To 1

            If a + b * x + c * y + d * (40 - 1 - x - y) = Num Then

               CheckNum = True

               Exit Function

            End If

         Next

      Next

   Next

Next

End Function