in reply to How do you match a stretch of at least N characters

Original post deleted. What I posted was completely wrong.

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Re^2: How do you match a stretch of at least N characters
by Anonymous Monk on Sep 12, 2017 at 19:27 UTC

    Original post deleted. What I posted was completely wrong.

    You're supposed to <strike></strike> out the wrong answer not delete

      Is this what you were looking for? The longest matching DNA string? You can save the max length found below to get your result.

      Answer:

      Found match of length (102) at position(506, 0):

      AAATTGGTGTATATGAAAGACCTCGACGCTATTTAGAAAGAGAGAGCAATATTTCAAGAATGCATGCGTCAATTTTACGCAGACTATCTTTCTAGGGTTAAT
      AAATTGGTGTATATGAAAGACCTCGACGCTATTTAGAAAGAGAGAGCAATATTTCAAGAATGCATGCGTCAATTTTACGCAGACTATCTTTCTAGGGTTAAA

      my $i=-1; while(++$i < length($reference_str)) { my $j=-1; while(++$j < length($small_str)) { my $length = 9; my $match=undef; while ( $i+$length < length($reference_str) and $j+$length < length($small_str) and compareSnippet($i, $j, ++$length) ) { $match++; } if ( $match) { $length--; print "Found match of length ($length) at position($i, $j): +\n"; print substr($reference_str, $i, $length) . "\n"; print substr($small_str, $j, $length). "\n"; $i+= $length; $j+= $length; next; } } } sub compareSnippet { my ( $pos_i, $pos_j, $length) = @_; my $ref = substr($reference_str, $pos_i, $length); my @ref_arr = sp +lit('', $ref); my $small = substr($small_str, $pos_j, $length); my @small_arr = sp +lit('', $small); return undef if length($ref) < $length or length($small) < $length; return equal(\@ref_arr, \@small_arr); } sub equal { my ($first, $second) = @_; my $mismatch=0; foreach my $i (0..(@$first-1)) { $mismatch++ if $first->[$i] ne $second->[$i]; return undef if $mismatch > 1; } # print "Woo! (@$first, @$second)\n" if $mismatch == 0; return 1; }