day 13 add

Author: gustafe

d13_1.pl

@@ -0,0 +1,89 @@
+#!/usr/bin/perl
+# Advent of Code 2016 Day 13 - part 1 
+# Problem link: http://adventofcode.com/2016/day/13
+#   Discussion: http://gerikson.com/blog/comp/Advent-of-Code-2016.html#d13
+#      License: http://gerikson.com/files/AoC2016/UNLICENSE
+###########################################################
+use 5.016;    # implies strict, provides 'say'
+use warnings;
+use autodie;
+
+#### INIT - load input data into array
+my $testing = 0;
+my ( $input, $target ) = ( 1358, [ 31, 39 ] );
+if ($testing) { $input = 10; $target = [ 7, 4 ]; }
+
+### CODE
+my $maze;
+my $seen;
+
+sub count_ones {
+
+    # http://docstore.mik.ua/orelly/perl/cookbook/ch02_05.htm
+    my $str = unpack( "B32", pack( "N", shift ) );
+    $str =~ s/^0+(?=\d)//;
+
+    my $count = 0;
+    for my $c ( split( //, $str ) ) {
+        $count++ if ( $c == 1 );
+    }
+    return $count;
+}
+
+sub is_open {
+    my ( $x, $y ) = @_;
+    if ( $x < 0 or $y < 0 ) { return 0 }
+    if ( exists $maze->{$x}->{$y} ) {
+        return $maze->{$x}->{$y};
+    }
+
+    my $fact = ( $x * $x + 3 * $x + 2 * $x * $y + $y + $y * $y );
+    $fact += $input;
+    my $ones = count_ones($fact);
+    if ( $ones % 2 == 0 ) {
+        $maze->{$x}->{$y} = 1;
+        return 1;
+    } else {
+        $maze->{$x}->{$y} = 0;
+        return 0;
+    }
+}
+
+my @states = ( [ 0, [ 1, 1 ] ] );
+LOOP: {
+    while (@states) {
+        my $move = shift @states;
+        my $step = $move->[0];
+        my ( $x, $y ) = @{ $move->[1] };
+
+        if ( exists $seen->{$x}->{$y} ) {
+            next;
+        } else {
+            $seen->{$x}->{$y}++;
+        }
+
+        # try to move
+        $step += 1;
+        my @new;
+        push @new,
+	  ( [ $x + 1, $y ], [ $x - 1, $y ],
+	    [ $x, $y + 1 ], [ $x, $y - 1 ] );
+
+        while (@new) {
+            my $el = shift @new;
+            my ( $new_x, $new_y ) = @$el;
+            if ( is_open( $new_x, $new_y ) ) {
+                if (     $new_x == $target->[0]
+                     and $new_y == $target->[1] )
+                {
+
+                    #break out reporting sucess
+                    say "steps: $step";
+                    last LOOP;
+                }
+                push @states, [ $step, $el ];
+            }
+        }
+
+    }
+}

d13_2.pl

@@ -0,0 +1,83 @@
+#!/usr/bin/perl
+# Advent of Code 2016 Day 13 - part 2
+# Problem link: http://adventofcode.com/2016/day/13
+#   Discussion: http://gerikson.com/blog/comp/Advent-of-Code-2016.html#d13
+#      License: http://gerikson.com/files/AoC2016/UNLICENSE
+###########################################################
+use 5.016;    # implies strict, provides 'say'
+use warnings;
+use autodie;
+
+#### INIT - load input data into array
+my $testing = 0;
+my ( $input, $target ) = ( 1358, [ 31, 39 ] );
+if ($testing) { $input = 10; $target = [ 7, 4 ]; }
+
+### CODE
+my $maze;
+my $seen;
+
+sub count_ones {    # http://docstore.mik.ua/orelly/perl/cookbook/ch02_05.htm
+    my $str = unpack( "B32", pack( "N", shift ) );
+    $str =~ s/^0+(?=\d)//;
+    my $count = 0;
+    for my $c ( split( //, $str ) ) {
+        $count++ if ( $c == 1 );
+    }
+    return $count;
+}
+
+sub is_open {
+    my ( $x, $y ) = @_;
+    if ( $x < 0 or $y < 0 ) { return 0 }
+    if ( exists $maze->{$x}->{$y} ) {
+        return $maze->{$x}->{$y};
+    }
+
+    my $fact = ( $x * $x + 3 * $x + 2 * $x * $y + $y + $y * $y );
+    $fact += $input;
+    my $ones = count_ones($fact);
+    if ( $ones % 2 == 0 ) {
+        $maze->{$x}->{$y} = 1;
+        return 1;
+    } else {
+        $maze->{$x}->{$y} = 0;
+        return 0;
+    }
+}
+
+my @states = ( [ 0, [ 1, 1 ] ] );
+
+while (@states) {
+    my $move = shift @states;
+    my $step = $move->[0];
+    my ( $x, $y ) = @{ $move->[1] };
+
+    if ( exists $seen->{$x}->{$y} ) {
+        next;
+    } else {
+        $seen->{$x}->{$y}++;
+    }
+
+    # try to move
+    $step += 1;
+    next if $step > 50;
+    my @new;
+    push @new,
+        ( [ $x + 1, $y ], [ $x - 1, $y ], [ $x, $y - 1 ], [ $x, $y + 1 ] );
+    while (@new) {
+        my $el = shift @new;
+        my ( $new_x, $new_y ) = @$el;
+        if ( is_open( $new_x, $new_y ) ) {
+            push @states, [ $step, $el ];
+        }
+    }
+}
+
+my $count = 0;
+for my $x ( keys %{$seen} ) {
+    for my $y ( keys %{ $seen->{$x} } ) {
+        $count++;
+    }
+}
+say $count;