A particular random number generator returns positive integer n with probability 1/(2^n). (ie '1' with probability 1/2, '2' with probability 1/4, '3' with probability 1/8, etc.)

Using this random number generator, write an algorithm which chooses a random integer from 1 to 37 with equal probability.

In Visual Basic (yeah I know it's not a real programming language...):

Dim I, J, IntArray(37), Temp As Integer

' Fill Integer Array with values from 1 to 37
For I = 1 To 37
    IntArray(I) = I
Next I

'Shuffle Array
For I = 1 To 37
    J = Rnd()
    Temp = IntArray(I)
    IntArray(I) = IntArray(J)
    IntArray(J) = Temp
Next I

Print IntArray(Rnd())

Stop
End

 

Posted by Erik O. on 2004-06-08 14:22:25