diff --git a/2019/08.cpp b/2019/08.cpp index cd71a24..471dbb7 100644 --- a/2019/08.cpp +++ b/2019/08.cpp @@ -4,51 +4,39 @@ #include #include #include +#include #include namespace { -using Layer = std::array; - -auto SplitLayers(std::istream & in) { - std::string line; - std::getline(in, line); - - std::vector layers; - - auto it = line.begin(); - auto layer_n = line.size() / 150; - for (std::size_t layer = 0; layer < layer_n; layer++) { - layers.push_back({}); - for (std::size_t y = 0; y < 150; y++) { - layers.back()[y] = *it++; - } - } - return layers; -} - -auto Part1(std::vector const& layers) { +auto Part1(std::string const& line) { std::size_t part1 = 0; - std::size_t seen = std::numeric_limits::max(); - for (auto & layer : layers) { - auto zeros = std::count(layer.begin(), layer.end(), '0'); + auto seen = std::numeric_limits::max(); + for (auto it = line.begin(); + std::distance(it, line.end()) >= 150; + std::advance(it, 150)) + { + auto zeros = std::count(it, it + 150, '0'); if (zeros < seen) { seen = zeros; part1 - = std::count(layer.begin(), layer.end(), '1') - * std::count(layer.begin(), layer.end(), '2'); + = std::count(it, it + 150, '1') + * std::count(it, it + 150, '2'); } } return part1; } -auto Flatten(std::vector const& layers) { - Layer merged {}; +auto Flatten(std::string const& line) { + std::string merged(150, ' '); for (std::size_t i = 0; i < 150; i++) { - for (auto & layer : layers) { - if ('2' != layer[i]) { - merged[i] = layer[i]; + for (auto it = line.begin(); + std::distance(it, line.end()) >= 150; + std::advance(it, 150)) + { + if ('2' != it[i]) { + merged[i] = it[i]; break; } } @@ -56,7 +44,7 @@ auto Flatten(std::vector const& layers) { return merged; } -auto Draw(Layer picture) { +auto Draw(std::string const& picture) { for (std::size_t y = 0; y < 6; y++) { for (std::size_t x = 0; x < 25; x++) { std::cout << ('1' == picture[y*25+x] ? "▓" : "░"); @@ -68,7 +56,8 @@ auto Draw(Layer picture) { } // namespace auto main(int argc, char** argv) -> int { - auto layers = SplitLayers(aocpp::Startup(argc, argv)); - std::cout << "Part 1: " << Part1(layers) << std::endl; - Draw(Flatten(layers)); + std::string line; + std::getline(aocpp::Startup(argc, argv), line); + std::cout << "Part 1: " << Part1(line) << std::endl; + Draw(Flatten(line)); }