aoc2021

commit e13810840718404f4a19fb0a28afd909dbe3bf75
parent 86abecef2c273ee73f272cd71ab52f95317728f1
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Thu, 23 Dec 2021 16:43:48 +0000

update day10-1.2.pl to provide working solution for Day 10 Part 1

Diffstat:
M
day10-1.2.pl
 | 
83
+++++++++++++++++++++++++++++++++++++------------------------------------------

1 file changed, 39 insertions(+), 44 deletions(-)
diff --git a/day10-1.2.pl b/day10-1.2.pl
@@ -18,57 +18,52 @@ sub get_filehandle {
 
 my $filehandle  =  get_filehandle();
 chomp( my @input = ( <$filehandle> ) );
-my @symbols  = qw( braces brackets parentheses comparison );
-my %symbol_count;
-my %count_map = (
-        '[' => ['braces',       1],
-        ']' => ['braces',      -1],
-        '{' => ['brackets',     1],
-        '}' => ['brackets',    -1],
-        '(' => ['parentheses',  1],
-        ')' => ['parentheses', -1],
-        '<' => ['comparison',   1],
-        '>' => ['comparison',  -1],
+my %closer_for = (
+        ']' => '[',
+        '}' => '{',
+        ')' => '(',
+        '>' => '<',
 );
-foreach my $line (@input) {
-    %symbol_count = map { $_ => 0 } @symbols; # reset count for each line
-    my $inner_most; # inner most opening character
-    say $line;
-
-# $symbol is each character (e.g. '[', '}', '(', '>') in the line.
-# The value of $count_map{$symbol} is a reference to a two-element array.
-# The first element of the array ([0]) is the name of matching open/close
-# character (e.g. "braces", "brackets", etc.)  The second element of that
-# array ([1]) is an integer which indicates whether it is an opening
-# character (1) or closing character (-1).  We can reference these array
-# values by dereferencing:
-#       $count_map{$symbol}->[0] or $count_map{$symbol}->[1]
-# These values are used to update the count of each symbol stored in
-# %symbol_count.
-
-    foreach my $symbol (split //, $line) {
-        say "$symbol $count_map{$symbol}->[0]\t$count_map{$symbol}->[1]";
-        $symbol_count{$count_map{$symbol}->[0]} += $count_map{$symbol}->[1];
-# if the symbol is an opening character, note that in $inner_most
-        $inner_most = $count_map{$symbol}->[0] if ($count_map{$symbol}->[0] == 1);
-        #print Dumper (\%symbol_count);
-    }
-    print Dumper (\%symbol_count);
-}
-
-my @openers = qw/ [ { ( < /;
-my @closers = qw/ ] } ) > /;
-say "@openers";
-say "@closers";
+my %opener_for = (
+        '[' => ']',
+        '{' => '}',
+        '(' => ')',
+        '<' => '>',
+);
+my %error_score = (
+        ']' => 57,
+        '}' => 1197,
+        ')' => 3,
+        '>' => 25137,
+);
+my $error_score = 0;
 foreach my $line (@input) {
     my @chunk;
     say $line;
     foreach my $symbol (split //, $line) {
-        if (grep { /$symbol/ } @openers) {
-            say "$symbol is an opener";
+# if the symbol is an opening symbol, add it to the @chunk array
+        if ( $symbol =~ m/\[|\{|\(|\</ ) {
+            push @chunk => $symbol;
+            print "$symbol is an opener.  ";
+            say "current chunk is @chunk";
         }
-        if (grep { /$symbol/ } @closers) {
+# if the symbol is a closing symbol...
+        if ( $symbol =~ m/\]|\}|\)|\>/ ) {
             say "$symbol is a closer";
+# ...check if the symbol is a closing symbol for the last opened one
+            if ($closer_for{$symbol} eq $chunk[-1]) {
+                say "$symbol is a matching closer";
+# pop off last opening symbol from the @chunk array
+                pop @chunk;
+                say "current chunk is @chunk";
+# otherwise, report an error
+            } else {
+                say "Expected $opener_for{$chunk[-1]}, but found $symbol instead.";
+                $error_score += $error_score{$symbol};
+                last; # go to next line
+            }
         }
     }
 }
+
+say "error score is $error_score";