in reply to Re: LCS efficiency problem
in thread LCS efficiency problem

Starting with 1 is part of the dynamic programming algorithm, no bug. 
 my @S = (undef, map { lc } split(/\w+/, $s));

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should fix the wordlists (so that eq is enough). Further filtering as suggested below is a good idea, do that!

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Re^3: LCS efficiency problem
by ikegami (Patriarch) on Jun 06, 2008 at 18:31 UTC

    Oops, missed the undef.

    But note that starting at one has nothing to do with the dynamic programming technique. If you wanted to start at zero (say if @S and @T are inputs to the function), then just replace 

                   $L[$i-1][$j-1] ||= 0;
               $L[$i][$j] = $L[$i-1][$j-1] + 1;

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    with 
                   if ($i && $j) {
                  $L[$i-1][$j-1] ||= 0;
                  $L[$i][$j] = $L[$i-1][$j-1] + 1;
               } else {
                  $L[$i][$j] = 1;
               }

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