临近学考，学习vb，于是打个spfa试试

Const maxn = 1000


Dim v(maxn), dis(maxn), nxt(maxn * 2), va(maxn * 2), first(maxn * 2), cnt As Integer
Dim n As Integer
Dim q(maxn * 5), head, tail As Integer
Dim inq(maxn) As Boolean
Public Sub addedge(u As Integer, vv As Integer, vaa As Integer)
    cnt = cnt + 1
    nxt(cnt) = first(u)
    first(u) = cnt
    va(cnt) = vaa
    v(cnt) = vv
End Sub


Private Sub Command1_Click()
    For i = 1 To n
        dis(i) = 32767
    Next i
    q(1) = Val(Text2.Text)
    dis(q(1)) = 0
    head = 1
    tail = 1
    While tail >= head
        Dim now, x As Integer
        x = q(head)
        now = first(q(head))
        While (now <> 0)
            If dis(v(now)) > dis(x) + va(now) Then
                If inq(v(now)) Then
                    tail = tail + 1
                    q(tail) = True
                End If
                dis(v(now)) = dis(x) + va(now)
            End If
            now = nxt(now)
        Wend
        inq(x) = False
        head = head + 1
    Wend
    For i = 1 To n
        List1.AddItem (Str(i) + " " + Str(dis(i)))
    Next i


End Sub


Private Sub Command2_Click()
    Call addedge(Val(Text1.Text), Val(Text3.Text), Val(Text4.Text))
End Sub


Private Sub Text5_Change()
    n = Val(Text5.Text)
End Sub