Day 12
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2 changed files with 203 additions and 7 deletions
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@ -12,7 +12,7 @@ set(CMAKE_CXX_COMPILER clang++)
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set(CMAKE_BUILD_TYPE Release)
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if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
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set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -Wno-c23-extensions -std=c++23}")
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set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -Wno-c23-extensions -std=c++23 -g")
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endif()
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set(executables d01 d02 d03 d04 d05 d06 d07 d08 d09 d10 d11 d12 d13 d14 d15 d16 d17 d18 d19 d20 d21 d22 d23 d24 d25)
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208
d12/main.cxx
208
d12/main.cxx
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@ -1,15 +1,211 @@
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#include <string>
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#include <sstream>
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#include <chrono>
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#include <iostream>
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#include <fstream>
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#include <vector>
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#include <unordered_map>
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#include <unordered_set>
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#include <algorithm>
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#include <ranges>
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using std::cout, std::endl;
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int main() {
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std::ifstream file{"../d12/input.txt"};
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std::string line;
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constexpr const char content[] = {
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#embed "input.txt"
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};
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while (std::getline(file, line)) {
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struct Position {
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int x;
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int y;
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bool operator==(const Position& other) const {
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return x == other.x && y == other.y;
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}
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};
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struct SidePosition {
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int x;
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int y;
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bool operator==(const Position& other) const {
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return x == other.x && y == other.y;
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}
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};
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struct Region {
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char type;
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std::vector<Position> positions;
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int perimeter;
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};
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struct SideRegion {
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char type;
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std::vector<SidePosition> positions;
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int corners;
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};
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namespace std {
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template <>
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struct hash<std::pair<int, int>> {
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size_t operator()(const std::pair<int, int>& p) const {
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return std::hash<int>{}(p.first) ^ std::hash<int>{}(p.second);
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}
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};
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}
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void find_region(std::vector<std::string>& garden, std::vector<Region>& regions, std::unordered_set<std::pair<int, int>>& visited, Position p, Region& curr_region, char target) {
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if(p.x < 0 || p.x >= garden.size() || p.y < 0 || p.y >= garden[p.x].size()) {
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return;
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}
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for(auto [i, j] : {std::pair{0, 1}, {0, -1}, {1, 0}, {-1, 0}}) {
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if(p.x + i >= 0 && p.x + i < garden.size() && p.y + j >= 0 && p.y + j < garden[p.x].size()) {
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if(garden[p.x + i][p.y + j] == target && !visited.contains({p.x + i, p.y + j})) {
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visited.insert({p.x + i, p.y + j});
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find_region(garden, regions, visited, {p.x + i, p.y + j}, curr_region, target);
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} else if(garden[p.x + i][p.y + j] != target){
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curr_region.perimeter++;
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}
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} else {
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curr_region.perimeter++;
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}
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}
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curr_region.positions.push_back(p);
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}
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int part_1() {
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std::istringstream input_stream(content);
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std::string line;
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std::vector<std::string> garden = {};
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std::vector<Region> regions = {};
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std::unordered_set<std::pair<int,int>> visited = {};
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while(getline(input_stream, line)) {
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garden.emplace_back(line);
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}
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int id = 0;
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for(int x = 0; x < garden.size(); x++) {
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for(int y = 0; y < garden[x].size(); y++) {
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if(!visited.contains({x, y})) {
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auto curr_region = Region{garden[x][y], {}, 0};
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visited.insert({x, y});
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find_region(garden, regions, visited, {x, y}, curr_region, garden[x][y]);
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regions.push_back(curr_region);
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}
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}
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}
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int total = 0;
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for(auto& region : regions) {
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total += region.perimeter * region.positions.size();
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}
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return total;
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}
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void find_corners(std::vector<std::string>& garden, std::vector<SideRegion>& regions, std::unordered_set<std::pair<int, int>>& visited, SidePosition p, SideRegion& curr_region, char target) {
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if(p.x < 0 || p.x >= garden.size() || p.y < 0 || p.y >= garden[p.x].size()) {
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return;
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}
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int edge_count = 0;
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for(auto [i, j] : {std::pair{0, 1}, {0, -1}, {1, 0}, {-1, 0}}) {
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if(p.x + i >= 0 && p.x + i < garden.size() && p.y + j >= 0 && p.y + j < garden[p.x].size()) {
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if(garden[p.x + i][p.y + j] != target) {
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edge_count++;
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}
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} else {
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edge_count++;
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}
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}
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if(edge_count == 0) {
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for(auto [i, j] : {std::pair{1, 1}, {1, -1}, {-1, 1}, {-1, -1}}) {
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if(p.x + i >= 0 && p.x + i < garden.size() && p.y + j >= 0 && p.y + j < garden[p.x].size()) {
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if(garden[p.x + i][p.y + j] != target) {
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edge_count++;
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}
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} else {
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edge_count++;
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}
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}
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if(edge_count == 1) {
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curr_region.corners++;
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}
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} else if(edge_count == 2) {
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curr_region.corners++;
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}
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for(auto [i, j] : {std::pair{0, 1}, {0, -1}, {1, 0}, {-1, 0}}) {
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if(p.x + i >= 0 && p.x + i < garden.size() && p.y + j >= 0 && p.y + j < garden[p.x].size()) {
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if(garden[p.x + i][p.y + j] == target && !visited.contains({p.x + i, p.y + j})) {
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visited.insert({p.x + i, p.y + j});
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find_corners(garden, regions, visited, {p.x + i, p.y + j}, curr_region, target);
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} else if(garden[p.x + i][p.y + j] != target){
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}
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} else {
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}
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}
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curr_region.positions.push_back(p);
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}
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int part_2() {
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std::istringstream input_stream(content);
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std::string line;
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std::vector<std::string> garden = {}, scaled_garden = {};
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std::vector<SideRegion> regions = {};
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std::unordered_set<std::pair<int,int>> visited = {};
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while(getline(input_stream, line)) {
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garden.emplace_back(line);
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}
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for(auto& row : garden) {
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std::string s{""};
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for(int i = 0; i < row.size(); i++) {
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for(auto _ : std::views::iota(0, 3)) {
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s.push_back(row[i]);
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}
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}
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for(auto _ : std::views::iota(0, 3)) {
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scaled_garden.push_back(s);
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}
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}
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int id = 0;
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for(int x = 0; x < scaled_garden.size(); x++) {
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for(int y = 0; y < scaled_garden[x].size(); y++) {
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if(!visited.contains({x, y})) {
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auto curr_region = SideRegion{scaled_garden[x][y], {}, 0};
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visited.insert({x, y});
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find_corners(scaled_garden, regions, visited, {x, y}, curr_region, scaled_garden[x][y]);
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regions.push_back(curr_region);
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}
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}
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}
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int total = 0;
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for(auto& region : regions) {
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total += region.corners * (region.positions.size()/9) ;
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}
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return total;
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}
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int main() {
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std::chrono::steady_clock::time_point begin = std::chrono::steady_clock::now();
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auto p1_val = part_1();
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std::chrono::steady_clock::time_point middle = std::chrono::steady_clock::now();
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auto p2_val = part_2();
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std::chrono::steady_clock::time_point end = std::chrono::steady_clock::now();
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cout << "Part 1: " << p1_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(middle - begin).count() << "µs)" << endl;
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cout << "Part 2: " << p2_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(end - middle).count() << "µs)" << endl;
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return 0;
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}
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