原文链接:https://www.f2er.com/vb/259479.html'本程序运行时耗时约为5-7秒。'以前在vb版回复问题时编写。
- VBScript code
Option Explicit Private Type mypoint x As Double y As Double End Type Dim p(0 To 49) As mypoint Dim smallcx As Double Dim smallcy As Double Dim smallr As Double Private Sub Form_Load() '开始时将smallr都置成很大 smallr = 1E+90 End Sub Private Function equ(ByVal a As Double,ByVal b As Double) As Boolean If Abs(a - b) < 0.000001 Then equ = True Else equ = False End If End Function Private Function Is_Three_Point_In_A_Line(ByVal x1 As Double,ByVal y1 As Double,ByVal x2 As Double,ByVal y2 As Double,ByVal x3 As Double,ByVal y3 As Double) As Boolean Dim a As Double,b As Double,e As Double a = (x1 + x2) * (x1 - x2) + (y1 + y2) * (y1 - y2) b = (x3 + x2) * (x3 - x2) + (y3 + y2) * (y3 - y2) e = (x1 - x2) * (y3 - y2) - (x2 - x3) * (y2 - y1) Is_Three_Point_In_A_Line = equ(e,0) End Function Private Sub Calc_TPC(ByVal x1 As Double,ByVal y3 As Double,cx As Double,cy As Double,r As Double) Dim a As Double,e As Double a = (x1 + x2) * (x1 - x2) + (y1 + y2) * (y1 - y2) b = (x3 + x2) * (x3 - x2) + (y3 + y2) * (y3 - y2) e = (x1 - x2) * (y3 - y2) - (x2 - x3) * (y2 - y1) cx = (a * (y3 - y2) + b * (y2 - y1)) / (2 * e) cy = (a * (x2 - x3) + b * (x1 - x2)) / (2 * e) r = Sqr((x1 - cx) * (x1 - cx) + (y1 - cy) * (y1 - cy)) End Sub Private Function incircle(ByVal cx As Double,ByVal cy As Double,ByVal r As Double,ByVal px As Double,ByVal py As Double) As Boolean Dim l1 As Double,l2 As Double l1 = px - cx l2 = py - cy If Sqr(l1 * l1 + l2 * l2) <= r Then incircle = True Else incircle = False End If End Function Private Sub Command1_Click() Cls Randomize Timer Dim i As Long,j As Long,k As Long Dim l As Long Dim cx As Double,r As Double Dim count As Long '先生成50个点,并显示在屏幕上 For i = 0 To 49 p(i).x = Rnd * 2000 p(i).y = Rnd * 2000 Me.Circle (p(i).x,p(i).y),15,vbRed Next i '计算所有的圆 For i = 0 To 49 For j = 0 To 49 For k = 0 To 49 If Not Is_Three_Point_In_A_Line(p(i).x,p(i).y,p(j).x,p(j).y,p(k).x,p(k).y) Then '三点可求圆 '求圆 Calc_TPC p(i).x,p(k).y,cx,cy,r '计算所有的点是否在圆内 count = 0 For l = 0 To 49 If incircle(cx,r,p(l).x,p(l).y) Then count = count + 1 End If Next l If count = 50 Then '所有的点都在圆内 If r < smallr Then smallcx = cx smallcy = cy smallr = r End If End If End If Next k Next j Next i '画出最小的圆 Circle (smallcx,smallcy),smallr,vbGreen End Sub
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