Another cook book - "The Practice of Programming" by Kernighan and Pike. And again, realization of "Markov chains algorithm" on page 123 can and must be optimized! So clever C/C++/Java examples and so ugly Perl example... :-(
#
# variant from "The Practice of Programming"
#
#!/usr/bin/perl
$MAXGEN = 10000;
$NONWORD = "\n";
$w1 = $w2 = $NONWORD;
while (<>) {
foreach (split) {
push(@{$statetab{$w1}{$w2}}, $_);
($w1, $w2) = ($w2, $_);
}
}
push(@{$statetab{$w1}{$w2}}, $NONWORD);
$w1 = $w2 = $NONWORD;
for ($i=0; $i<$MAXGEN; $i++) {
$suf = $statetab{$w1}{$w2};
$r = int(rand @$suf);
exit if (($t = $suf->[$r]) eq $NONWORD);
print "$t\n";
($w1, $w2) = ($w2, $t);
}
#
# my variant
#
#!/usr/bin/perl -a0n
push @{$m{$F[$_-1]}{$F[$_]}}, $F[$_+1] for 1..$#F;
1 while defined($F[2+$i++] = splice @{$m{$F[0+$i]}{$F[1+$i]}},
rand(@{$m{$F[0+$i]}{$F[1+$i]}}), 1);
print join(" ",@F[0..1+$i]),"\n";
