And the culprit was ... usage of self-documenting variable names.

Simply avoiding the array-copy my @path=@_ makes a factor 4.5 performance boost...

Fascinating!!! What a pity Perl doesn't support aliasing out of the box!

{
  my %seen;
  sub track {
    my $last=$_[-1];
    $seen{$last}=1;
 
    for my $next (@{$graph{$last}}) {
      next if $seen{$next};
      if ($next eq $stop) {
        #print join ("->",@_,$stop),"\n";
        $anzahl++;
        print "$anzahl at ",time-$time0,"\n" if $anzahl%10000==0;
      } else {
        track(@_,$next);
      }  
    }
    delete $seen{$last};
  }
}

[download]

Cheers Rolf

In reply to Re^11: Finding All Paths From a Graph From a Given Source and End Node by LanX
in thread Finding All Paths From a Graph From a Given Source and End Node by neversaint

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