[104874] in Cypherpunks
Re: Random array
daemon@ATHENA.MIT.EDU (=?iso-8859-1?Q?Jes=FAs?= Cea =?iso)
Fri Oct 30 10:49:06 1998
Date: Fri, 30 Oct 1998 14:59:05 -0100
From: =?iso-8859-1?Q?Jes=FAs?= Cea =?iso-8859-1?Q?Avi=F3n?= <jcea@argo.es>
To: Lista Coderpunks <coderpunks@toad.com>
Reply-To: =?iso-8859-1?Q?Jes=FAs?= Cea =?iso-8859-1?Q?Avi=F3n?= <jcea@argo.es>
> >for j from 255 down to 1
> > pick random number k from 0 through j
> > swap items j and k
I'd rather prefer
for i in 1..n
j = random(1..n)
swap(a[i],a[j])
So, each position has equal posibilities. Since random+random=random
:-), each cell is visited one time, and the element placed there is
random and taken from the entire set, the final array will be random.
--
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