Programming Interview Questions

You have a stream of numbers that you can see one at a time. With uniform probability, select only one of these numbers. That is, each number in the stream has the same probability of being selected. You cannot just store the entire stream to an array or read through the stream twice.

>>12
Just tested it quickly:


Private Sub Form_Load()
    Dim k(100) As Integer
    For j = 1 To 10000
    o = 0
    For i = 1 To 100
        If Rnd < 1 / i Then o = i
    Next i
    k(o) = k(o) + 1
    Next j
   
    For j = 1 To 100
        Me.Line (j, 100)-(j, 100 - k(j)), 0
    Next j
End Sub

Yes, VB6 is an embarrassment, but it works and produces an even distribution reliably. So EAT IT.