aoc2015

commit 0cece4b6c7ecf0670a0f9fb616dd9e96c0ff9a9e
parent a187095cec4c0a1409d595d7ca6e37158d0065d3
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Sat, 12 Nov 2022 16:58:37 +0000

solve part 2 of day20

Diffstat:
M
day20/day20.pl
 | 
39
+++++----------------------------------

1 file changed, 5 insertions(+), 34 deletions(-)
diff --git a/day20/day20.pl b/day20/day20.pl
@@ -4,7 +4,6 @@
 use strict;
 use warnings;
 use v5.32;
-use lib '.';
 use Math::Prime::Util qw( divisors );
 use List::Util        qw( sum );
 
@@ -14,41 +13,13 @@ my $house_number = 1;
 $house_number++ while ( sum( divisors( $house_number ) ) * 10 < $input );
 say "part 1: ", $house_number;
 
-
-#my $NUM_ELVES = 8;
 my $MAX_HOUSES = 50;
 my $PRESENTS_PER_HOUSE = 11;
-my %presents;
-my $target = 400;
-my $elf = 1;
+$house_number = 1;
 
-#foreach my $elf ( 1 .. $NUM_ELVES ) {
 while (1) {
-    my $house_number = $elf;
-    foreach my $house ( 1 .. $MAX_HOUSES ) {
-        print "elf $elf is delivering ", $elf * $PRESENTS_PER_HOUSE, " presents to house $house_number ";
-        $presents{ $house_number } += $elf * $PRESENTS_PER_HOUSE;
-        say "which now has $presents{$house_number} presents";
-        if ( $presents{ $house_number } >= $input ) {
-            say "part 2: ", $house_number;
-            exit;
-        }
-        $house_number += $elf;
-    }
-    $elf++;
+    my $presents = $PRESENTS_PER_HOUSE * sum(grep { $_ >= $house_number/$MAX_HOUSES } divisors($house_number));
+    last if $presents >= $input;
+    $house_number++;
 }
-
-
-#foreach my $elf ( 1 .. $NUM_ELVES ) {
-#    my $house_number = $elf;
-#    foreach my $house ( 1 .. $MAX_HOUSES ) {
-#        print "elf $elf is delivering ", $house_number * $PRESENTS_PER_HOUSE, " presents to house $house_number ";
-#        $presents{ $house_number } += $house_number * $PRESENTS_PER_HOUSE;
-#        say "which now has $presents{$house_number} presents";
-#        if ( $presents{ $house_number } > $target ) {
-#            say "part 2: ", $house_number;
-#            exit;
-#        }
-#        $house_number += $elf;
-#    }
-#}
+say "part 2: ", $house_number;