day20

20/1.pl

@@ -0,0 +1,38 @@
+use 5.20.0;
+use List::AllUtils qw/ sum /;
+use List::UtilsBy qw/ nsort_by /;
+
+use DDP; 
+
+my $i;
+my @raw = map { [ map { [ split ',' ] } /[pva]=<(.*?)>/g ] } <>;
+my @p = map { [ map { manhat(@$_) } @$_ ] } @raw;
+
+for ( sort {
+    $p[$a][2] <=> $p[$b][2]
+        or
+    $p[$a][1] <=> $p[$b][1]
+        or
+    $p[$a][0] <=> $p[$b][0]
+} 0..$#p ) {
+#    p $raw[$_];
+    p $p[$_];
+    say $_;
+    exit if $i++ >= 3;
+}
+
+
+sub manhat { sum map { abs } @_ }
+
+p @p;
+
+my( $min ) = sort {
+    $p[$a][2] <=> $p[$b][2]
+        or
+    $p[$a][1] <=> $p[$b][1]
+        or
+    $p[$a][0] <=> $p[$b][0]
+} 0..$#p;
+
+say $min;
+

20/2.pl

@@ -0,0 +1,37 @@
+use 5.20.0;
+use List::AllUtils qw/ sum uniq /;
+use List::UtilsBy qw/ nsort_by /;
+
+use experimental qw/ postderef smartmatch /;
+
+use DDP; 
+
+my $i;
+my @raw = map { [ map { [ split ',' ] } /[pva]=<(.*?)>/g ] } <>;
+
+while() {
+    check_collisions();
+    move_particles();
+    say scalar @raw;
+}
+
+sub move_particles {
+    for ( @raw ) {
+        for my $i ( 0..2 ) {
+            $_->[1][$i] += $_->[2][$i];
+            $_->[0][$i] += $_->[1][$i];
+        }
+    }
+}
+
+sub check_collisions {
+    my %seen;
+    my @to_delete;
+    for ( 0..$#raw ) {
+        my $k = join ':', $raw[$_][0]->@*;
+        push @to_delete, $seen{$k}, $_ if exists $seen{$k};
+        $seen{$k} = $_;
+    }
+    return unless @to_delete;
+    @raw = @raw[ grep { not $_ ~~ @to_delete }  0..$#raw ];
+}