aoc2022

commit 57d851b9ce3c419e041b1bd6bcaeca8f9db032a0
parent 22b3dbc918368c5c876a085e659e7fe82291d965
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Mon,  2 Jan 2023 18:07:14 +0000

solve part 2 of day11

Diffstat:
A
day11/day11.2.pl
 | 
116
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 116 insertions(+), 0 deletions(-)
diff --git a/day11/day11.2.pl b/day11/day11.2.pl
@@ -0,0 +1,116 @@
+#!/usr/local/bin/perl
+# day 2022-11
+
+use strict;
+use warnings;
+use v5.32;
+
+use List::Util qw( product );
+
+use Log::Log4perl ();
+use Log::Log4perl::Level ();
+Log::Log4perl->easy_init(
+    Log::Log4perl::Level::to_priority( 'OFF' )
+); # set to 'OFF', 'INFO', 'DEBUG' or 'TRACE'  for successively more information
+my $logger = Log::Log4perl->get_logger();
+
+@ARGV = "input" unless @ARGV;
+$/ = ''; # set to paragraph mode.  Each monkey is treated as one record
+my @input = <>;
+
+my $ITEMS       = "items";
+my $OPERATION   = "Operation";
+my $TEST        = "Test";
+my $TRUE        = "true";
+my $FALSE       = "false";
+my $ROUNDS      = 10000;
+
+sub init_monkeys {
+    my @input = @_;
+    my @monkeys;
+    foreach my $monkey ( @input ) {
+        my %monkey;
+        foreach my $attribute ( split /\n/, $monkey ) {
+            next if ( $attribute =~ m/Monkey/ );
+            my ( $key, $value ) = split /:/ => $attribute;
+            if ( $key =~ m/$ITEMS/ ) {
+                $value =~ s/\s//g;
+                $monkey{ $ITEMS } = [ split /,/ => $value ];
+            } elsif ( $key =~ m/$OPERATION/ ) {
+                my %operation;
+                my ( $operation, $operand ) = $value =~ m/(\+|\*) (.+)/;
+                $monkey{ $OPERATION } = { "operation" => $operation,
+                                          "operand"   => $operand,
+                                        };
+            } elsif ( $key =~ m/$TEST/ ) {
+                ( $monkey{ $TEST } )  = $value =~ m/(\d+)/;
+            } elsif ( $key =~ m/$TRUE/ ) {
+                ( $monkey{ $TRUE } )  = $value =~ m/(\d+)/;
+            } elsif ( $key =~ m/$FALSE/ ) {
+                ( $monkey{ $FALSE } ) = $value =~ m/(\d+)/;
+            } else {
+                die "Could not parse attribute $attribute";
+            }
+        }
+        push @monkeys => \%monkey;
+    }
+    return @monkeys;
+}
+
+my @monkeys1 = init_monkeys( @input );
+my %monkeys1_count;
+
+my $modulo = 1;
+$modulo *= $_->{ $TEST } foreach ( @monkeys1 );
+$logger->trace( "modulo = $modulo" );
+
+foreach my $round ( 1 .. $ROUNDS ) {
+    my $num = 0;
+    foreach my $monkey ( @monkeys1 ) {
+        $logger->trace( "Monkey $num:" );
+        while ( @{ $monkey->{ $ITEMS } } ) {
+            my $item = shift @{ $monkey->{ $ITEMS } };
+            $logger->trace( "  Monkey inspects an item with a worry level of $item." );
+            $monkeys1_count{ $num }++;
+            my $expression = join " ",
+                             $item,
+                             $monkey->{ $OPERATION }{ operation },
+                             $monkey->{ $OPERATION }{ operand   } eq 'old' ? $item :
+                             $monkey->{ $OPERATION }{ operand   };
+            $item = eval $expression;
+            $item = $item % $modulo;
+            $logger->trace( "    Worry level is now $item." );
+            #$item = int( $item / 3 );
+            #$logger->trace("    Monkey gets bored with item. ",
+            #               "Worry level is divided by 3 to $item.");
+            if ( $item % $monkey->{ $TEST } == 0 ) { # true
+                $logger->trace( "    Current worry level is divisible by ",
+                                "$monkey->{ $TEST }." );
+                $logger->trace( "    Item with worry level $item is thrown to monkey ",
+                                "$monkey->{ $TRUE }." );
+                push @{ $monkeys1[ $monkey->{ $TRUE } ]->{ $ITEMS } } => $item;
+            } else { # false
+                $logger->trace( "    Current worry level is not divisible by ",
+                                "$monkey->{ $TEST }." );
+                $logger->trace( "    Item with worry level $item is thrown to monkey ",
+                                "$monkey->{ $FALSE }." );
+                push @{ $monkeys1[ $monkey->{ $FALSE } ]->{ $ITEMS } } => $item;
+            }
+        }
+        $num++;
+    }
+
+    $logger->debug( "After round $round, the monkeys are holding items with these ",
+                    "worry levels:" );
+    foreach my $i ( 0 .. $#monkeys1 ) {
+        $logger->debug( "Monkey $i: ",
+                        ( join ", ", @{ $monkeys1[ $i ]->{ $ITEMS } } ) );
+    }
+}
+
+foreach my $monkey ( sort keys %monkeys1_count ) {
+    $logger->info( "Monkey $monkey inspected items $monkeys1_count{ $monkey } times." );
+}
+
+my @inspections = reverse( sort { $a <=> $b } ( values %monkeys1_count ) );
+say "part 2: ", product @inspections[ 0 .. 1 ];