part1

2018/06/input.txt

@@ -0,0 +1,50 @@
+275, 276
+176, 108
+270, 134
+192, 224
+252, 104
+240, 271
+144, 220
+341, 303
+344, 166
+142, 347
+207, 135
+142, 353
+343, 74
+90, 210
+82, 236
+124, 295
+41, 226
+298, 109
+276, 314
+50, 303
+131, 42
+119, 335
+275, 125
+113, 289
+347, 230
+192, 329
+158, 316
+154, 356
+171, 350
+165, 59
+257, 129
+306, 55
+334, 203
+55, 63
+268, 198
+44, 103
+230, 199
+41, 181
+357, 328
+331, 85
+256, 290
+168, 290
+353, 77
+81, 328
+136, 316
+138, 213
+352, 271
+139, 222
+139, 318
+194, 239

2018/06/sol1.pl

@@ -0,0 +1,92 @@
+use 5.20.0;
+use warnings;
+
+use List::AllUtils qw/ minmax pairs uniq /;
+use List::UtilsBy qw/ max_by /;
+
+use experimental qw/
+    signatures
+    postderef
+/;
+
+my @points = map { [ split ', ' ] } <>;
+
+my @range_x = minmax map { $_->[0] } @points;
+my @range_y = minmax map { $_->[1] } @points;
+
+use DDP;
+
+p @range_x;
+p @range_y;
+
+my @grid;
+my $id = 'a';
+my @infinite;
+
+my @movers = map {
+    $id++;
+    [ $id, 0, @$_ ]
+} @points;
+
+while( my $next = shift @movers ) {
+    calculate_distances( @$next );
+}
+
+push @infinite,
+    uniq
+    map { eval { $_->[1]->@* } }
+    grep { $_ and 1 == $_->[1]->@* }
+    map { $grid[$_]->@* }    $range_x[0]-1, $range_x[1]+1;
+
+my %tally;
+
+for my $x ( map { eval { $_->[1] } } map { eval { @$_ } } @grid ) {
+    next unless ref $x;
+    next if 1 < @$x;
+    $tally{ $x->[0] }++;
+}
+
+delete @tally{@infinite};
+
+my $max = max_by { $_->[1] } pairs %tally;
+
+p $max;
+
+# for my $row ( @grid ) {
+#     say map { $_ ?
+#             ($_->[1]->@* > 1 ? ' ' : $_->[1]->@* ) : '' } @$row
+# }
+
+
+sub calculate_distances($id, $distance, $x, $y) {
+
+    if( $x < $range_x[0] - 1
+            or $x > $range_x[1] +1
+            or $y < $range_y[0] - 1
+            or $y > $range_y[1] +1 ) { return; }
+
+    if( !$grid[$x][$y] ) {
+        $grid[$x][$y] = [ $distance, [ $id ] ];
+    }
+    else {
+        if( $distance < $grid[$x][$y][0] ) {
+            $grid[$x][$y] = [ $distance, [ $id ] ];
+        }
+        elsif( $distance == $grid[$x][$y][0] ) {
+            if( grep { $_ eq $id } $grid[$x][$y][1]->@* ) { return }
+            push $grid[$x][$y][1]->@*, $id;
+            return;
+        }
+        else {
+          return;
+        }
+    }
+
+    $distance++;
+
+    push @movers,
+        [ $id, $distance, $x+1, $y ],
+        [ $id, $distance, $x-1, $y ],
+        [ $id, $distance, $x, $y+1 ],
+        [ $id, $distance, $x, $y-1 ];
+}

2018/06/test.txt

@@ -0,0 +1,6 @@
+1, 1
+1, 6
+8, 3
+3, 4
+5, 5
+8, 9