Re: Random Derangement Of An Array

[jacques]

in reply to Random Derangement Of An Array

sub fisher_yates_shuffle {
        my $deck = shift;  # $deck is a reference to an array
        my $i = @$deck;
        while ($i--) {
            my $j = int rand ($i+1);
            @$deck[$i,$j] = @$deck[$j,$i];
        }
    }

my @list = (1..5);
fisher_yates_shuffle( \@list );
print join ', ',@list;

[Limbic~Region]

jacques,
Is this a modified Fisher-Yates shuffle? I am too tired to tell. If it isn't, then it won't work because a shuffle is not guaranteed to generate a derangement. If it is - please explain the modification.