day 4 part 2 solution

baton · baton · commit 0d95eb4aaad4 · 2021-12-06T17:26:50.000+03:00
diff --git a/04/2.cpp b/04/2.cpp
@@ -0,0 +1,132 @@
+#include <iostream>
+#include <fstream>
+#include <iterator>
+#include <string>
+#include <vector>
+#include <array>
+#include <algorithm>
+#include <numeric>
+
+#include <boost/spirit/include/qi.hpp>
+
+namespace qi = boost::spirit::qi;
+
+size_t constexpr game_size{ 5 };
+
+
+using value_t = std::pair< uint64_t, bool >;
+using line_t = std::array< value_t, game_size >;
+using card_t = std::array< line_t, game_size * 2 >;
+using cards_t = std::vector< card_t >;
+
+
+int main( int argc, char * argv[] )
+{
+	if( argc < 2 )
+		return 0;
+
+	std::ifstream ifs( argv[ 1 ] );
+
+	std::vector< uint64_t > game;
+	std::string sinp;
+	ifs >> sinp;
+	if( !qi::phrase_parse( sinp.cbegin(), sinp.cend(), qi::int_ % ',', qi::space, game ) )
+	{
+		std::cout << "parse error" << std::endl;
+		return 0;
+	}
+
+	cards_t cards;
+	while( !ifs.eof() )
+	{
+		std::array< uint64_t, game_size * game_size > nums;
+		for( uint64_t & n : nums )
+			ifs >> n;
+
+		card_t card;
+		for( size_t i( 0 ); i != game_size; ++i )
+			for( size_t j( 0 ); j != game_size; ++j )
+			{
+				card[ i ][ j ] = { nums[ i * game_size + j ], false };
+				card[ i + 5 ][ j ] = { nums[ j * game_size + i ], false };
+			}
+
+		cards.push_back( std::move( card ) );
+	}
+
+	cards_t out;
+	uint64_t last_number{ 0 };
+	for( uint64_t const & number : game )
+	{
+		for( card_t & card : cards )
+		{
+			for( line_t & line : card )
+			{
+				auto i = std::find( line.begin(), line.end(), std::make_pair( number, false ) );
+				if( i != line.end() )
+					i->second = true;
+			}
+		}
+
+		auto outed{
+			std::remove_if( cards.begin(), cards.end(),
+				[]( card_t const & card ) -> bool
+				{
+					return std::transform_reduce( card.begin(), card.end(),
+						false,
+						std::logical_or(),
+						[]( line_t const & line ) -> bool
+						{
+							return std::transform_reduce( line.begin(), line.end(),
+								true,
+								std::logical_and(),
+								[]( value_t const & v ) -> bool
+								{
+									return v.second;
+								}
+							);
+						}
+					);
+				}
+			)
+		};
+		if( outed != cards.end() )
+		{
+			out.insert( out.end(), outed, cards.end() );
+			cards.erase( outed, cards.end() );
+		}
+
+		last_number = number;
+		if( cards.empty() )
+			break;
+	}
+
+	if( !out.empty() )
+	{
+		card_t const & card( out.back() );
+
+		uint64_t const sum_unmarked{
+			std::transform_reduce( card.begin(), card.begin() + game_size,
+				0ULL,
+				std::plus(),
+				[]( line_t const & line ) -> uint64_t
+				{
+					return std::transform_reduce( line.begin(), line.end(),
+						0ULL,
+						std::plus(),
+						[]( value_t const & v ) -> uint64_t
+						{
+							return v.second ? 0ULL : v.first;
+						}
+					);
+				}
+			)
+		};
+
+		std::cout << "result = " << ( last_number * sum_unmarked ) << std::endl;
+
+		return 0;
+	}
+
+	return 0;
+}
