diff options
| -rwxr-xr-x | challenge-248/mattneleigh/perl/ch-1.pl | 67 |
1 files changed, 53 insertions, 14 deletions
diff --git a/challenge-248/mattneleigh/perl/ch-1.pl b/challenge-248/mattneleigh/perl/ch-1.pl index d685799252..e0e5d44c09 100755 --- a/challenge-248/mattneleigh/perl/ch-1.pl +++ b/challenge-248/mattneleigh/perl/ch-1.pl @@ -14,6 +14,10 @@ my @strings_and_characters = ( [ "aaab", "b" ], # Additional test cases + [ "computersarefun", "e" ], + [ "programmingrules", "p" ], + [ "greatforproblemsolving", "g" ], + [ "lovelexicalvariables", "x" ], [ "perliscool", "x" ] ); @@ -52,18 +56,20 @@ exit(0); # the string ################################################################################ sub relative_distances_to_character{ - # Required for @LAST_MATCH_START (@-) - use v5.6; - use List::Util qw(min); + my $current_loc = 0; my @matches; - my $current = 0; + my $char = substr($ARG[1], 0, 1); # Attempt to match the character in the # string, taking note of the location of - # each occurrence - while($ARG[0] =~ m/$ARG[1]/g){ - push(@matches, $LAST_MATCH_START[0]); + # each occurrence; this is faster than + # regex for this simple case + foreach my $current_char (split('', $ARG[0])){ + push(@matches, $current_loc) + if($char eq $current_char); + + $current_loc++; } # Return an empty list if the character @@ -71,19 +77,52 @@ sub relative_distances_to_character{ return( () ) unless(@matches); + my $dist_ahead; + my $dist_behind; + + $current_loc = 0; + return( # Make a list of relative distances to # the nearest character match for each # position within the string map( { - $current++ - if($_ > $matches[$current]); - - min( - abs($_ - $matches[$current - 1]), - abs($_ - $matches[$current]) - ); + if($_ <= $matches[0]){ + # We're at or before the first match + # in the list; also covers cases of + # just one match + $matches[0] - $_; + } elsif($_ >= $matches[$#matches]){ + # We're at or beyond the last match in + # the list; also covers cases of just + # one match + $_ - $matches[$#matches]; + } else{ + # We're between matches... + + # Increment the current match position + # if we've passed the previous one + $current_loc++ + if($_ > $matches[$current_loc]); + + # Get distances to the nearest matches + # ahead and behind + $dist_behind = $_ - $matches[$current_loc - 1]; + $dist_ahead = $matches[$current_loc] - $_; + + # See which distance is smaller; doing + # it this way is somewhat faster for + # this simple case than calling + # List::Util::min() directly on the + # values involved, on most systems- as + # long as the variables are lexically + # scoped outside of this block + $dist_behind < $dist_ahead ? + $dist_behind + : + $dist_ahead; + } } 0 .. length($ARG[0]) - 1 ) |