让我来提高吧里帖子的质量

先求大神算一下，我们好对个答案

概率变化矩阵如下（每一排当中，从某位置进入，某位置出来的概率；比如，如果2进去那么1出来的概率是0）

（再考虑出来时候等概率分布到两边）然后动态规划一下；
最终结果如下：

这当初可是楼主花了整整一个下午写程序算的，累死朕了。

Ps：程序代码下附（vb）：（一般很少有人愿意发程序代码的，劳动成果啊）
Dim qk(1 To 5) As Integer
Dim i As Integer
Dim n As Integer
Dim ji As Integer
Dim jg(5) As Single
Dim j(1 To 5, 1 To 5) As Single
Dim zong(1 To 5) As Single
Function ken(x As Integer, gailv As Single)
If qk(x) > 1 Then
qk(x) = qk(x) - 1
Else
jg(x) = jg(x) + gailv
GoTo 1
End If
Dim m
Select Case x
Case 1:
m = ken(2, gailv)
Case 5:
m = ken(4, gailv)
Case Else:
m = ken(x + 1, 0.5 * gailv)
m = ken(x - 1, 0.5 * gailv)
End Select
qk(x) = qk(x) + 1
1:
End Function
Function jin(x As Integer, gailv As Single)
If ji = 9 Then
zong(x) = zong(x) + gailv
GoTo 1
End If
Dim m
ji = ji + 1
m = jin(1, gailv * 0.5 * j(x, 2))
m = jin(2, gailv * 0.5 * (2*j(x, 1) + j(x,3)))
m = jin(3, gailv * 0.5 * (j(x, 2) + j(x,4)))
m = jin(4, gailv * 0.5 * (j(x, 3) + 2*j(x,5)))
m = jin(5, gailv * 0.5 * j(x, 4))
ji = ji - 1
1:
End Function
Private Sub Command1_Click()
Dim m
ji = 1
For n = 1 To 5
zong(n) = 0
For i = 1 To 5
qk(i) = 5
jg(i) = 0
Next i
m = ken(n, 1)
For i = 1 To 5
j(n, i) = jg(i)
Next i
Next n
m = jin(3, 1)
Open App.Path & "\123.TXT"For Output As #1
For n = 1 To 5
For i = 1 To 5
Print #1, n & " " & i& " " & j(n, i)
Next
Next
Print #1, "最终1到5位置概率是："
For i = 1 To 5
Print #1, zong(i)
Next
Print #1, "3位置概率是"& zong(3)
Close #1
*打印结果
End Sub

所以我们得到，最终的结果是0.3780686当然这里已经取了近似值。