wip

2023/08/Part2.pm

@@ -4,30 +4,86 @@ package Part2;
 
 use Part1;
 
-use List::AllUtils qw/all /;
+use List::AllUtils qw/all first_index none min max /;
+
+sub get_cycle( $current, $directions, $nodes ) {
+
+    my @tracks;
+    my $next_index = 0;
+
+    while() {
+    use DDP; #p @tracks;
+        my $t = join '-',  $current,$next_index;
+        my $i = first_index { $_ eq $t } @tracks;
+        if( $i > -1 ) {
+            my $c = 0;
+            #   p @tracks;
+            # warn $i, " ",$t;
+            return $i, map {
+                $c++;
+                if(/Z-/) {
+                    my $x = $c; $c = 0; $x;
+                }else {
+                    ()
+                }
+            } splice @tracks, $i;
+        }
+        push @tracks, $t;
+        $current = $nodes->{$current}[ $directions->[ $next_index ] ];
+        $next_index = ( $next_index+1)% @$directions;
+    }
+
+
+}
 
 sub solution_2 ($input) {
     my $p          = Part1::parse_input($input);
     my @directions = $p->{directions}->@*;
     my %nodes      = $p->{nodes}->%*;
 
+    my @paths;
+    my @initial = grep { /A$/ } keys %nodes;
+    for (@initial ) {
+        push @paths, [
+            Part2::get_cycle($_,\@directions,\%nodes)
+        ];
+    }
+
     my $visited = 0;
-    my $next_index = 0;
-    my @current    = grep { /A$/ } keys %nodes;
+    my @preloop = map { shift @$_   } @paths;
+    p @preloop;
+    my $pre = max @preloop;
+    $visited += $pre;
 
-    until ( all { /Z$/ } @current ) {
-        # use DDP; p @current;
-        # my $foo = <>;
-        $visited++;
+    my @current = map { $preloop[$_] - $pre } 0..$#preloop;
+        p @current;p @paths;
+    for(0..$#current) {
+            while( $current[$_] <= 0 ) {
+                $current[$_] += $paths[$_][0];
+                push $paths[$_]->@*, shift $paths[$_]->@*;
+            }
+    }
+        p @current;p @paths;
 
-        @current = map {
-          $nodes{$_}->[ $directions[ $next_index % @directions ] ]
-      } @current;
-      $next_index++;
+    until( none { $_ } @current ) {
+        use DDP; 
+        warn $visited;
+        p @current;p @paths;
+        my $incr = max @current;
+        warn $incr;
+        $visited += $incr;
+        for ( 0..$#current) {
+            $current[$_] -=  $incr;
+            while( $current[$_] < 0 ) {
+                $current[$_] += $paths[$_][0];
+                push $paths[$_]->@*, shift $paths[$_]->@*;
+            }
+        }
     }
 
     return $visited;
 
+
 }
 
 1;

2023/08/part2.t

@@ -8,10 +8,7 @@ use File::Serialize;
 use Part2;
 
 my $input = path('input')->slurp;
-my $example   = path('example')->slurp;
-my %solutions = deserialize_file('solutions.yml')->%*;
-
-is Part2::solution_2(<<'END') => 6;
+my $example   = <<END;
 LR
 
 11A = (11B, XXX)
@@ -23,6 +20,27 @@ LR
 22Z = (22B, 22B)
 XXX = (XXX, XXX)
 END
+my %solutions = deserialize_file('solutions.yml')->%*;
+
+
+my $parsed = Part1::parse_input($example);
+is [Part2::get_cycle('11A',$parsed->{directions},$parsed->{nodes})] => [1,2];
+#use DDP; my @x =  Part2::get_cycle('22A',$parsed->{directions},$parsed->{nodes});p @x;
+is [Part2::get_cycle('22A',$parsed->{directions},$parsed->{nodes})] => [1,2,3];
+
+
+is Part2::solution_2($example) => 6;
+exit;
+
+
+
+$parsed = Part1::parse_input($input);
+
+# my @initial = grep { /A$/ } keys $parsed->{nodes}->%*;
+# for (@initial ) {
+#     say join " ", Part2::get_cycle($_,$parsed->{directions},$parsed->{nodes});
+# }
+
 
 is Part2::solution_2($input) => $solutions{2};