Day 12 Task 1

CMakeLists.txt

@@ -12,7 +12,7 @@ file(GLOB_RECURSE SRC_FILES src/**.cpp)
 add_executable(AdventOfCode2023 ${SRC_FILES})
 
 include(FetchContent)
-FetchContent_Declare(cpr GIT_REPOSITORY https://github.com/libcpr/cpr.git GIT_TAG 100cf2050be7619430a615cd0d580b33c62fde6b)
+FetchContent_Declare(cpr GIT_REPOSITORY https://github.com/libcpr/cpr.git GIT_TAG 3b15fa8)
 FetchContent_MakeAvailable(cpr)
 
 target_link_libraries(AdventOfCode2023 cpr::cpr)

src/days/11/Day11.cpp

@@ -29,38 +29,15 @@ Result Day11::Task1() {
 		}
 	}
 
-	vector<Coord> galaxies;
-	for (size_t y = 0; y < universe.size(); y++){
-		auto row = universe[y];
-		for (size_t x = 0; x < row.size(); x++)
-			if (universe[y][x])
-				galaxies.emplace_back(x, y);
-	}
-
-	uint64 sum = 0;
-
-	for (size_t i = 0; i < galaxies.size(); i++){
-		for (size_t j = i + 1; j < galaxies.size(); j++){
-			auto &[x1, y1] = galaxies[i];
-			auto &[x2, y2] = galaxies[j];
+	auto galaxies = getGalaxies(universe);
 
-			sum += std::abs(long(x2 - x1)) + std::abs(long(y2 - y1));
-		}
-	}
-
-	return to_string(sum);
+	return to_string(getDistanceSum(galaxies));
 }
 
 Result Day11::Task2() {
 	Universe universe = parseUniverse();
 
-	vector<Coord> galaxies;
-	for (size_t y = 0; y < universe.size(); y++){
-		auto row = universe[y];
-		for (size_t x = 0; x < row.size(); x++)
-			if (universe[y][x])
-				galaxies.emplace_back(x, y);
-	}
+	auto galaxies = getGalaxies(universe);
 
 	const size_t gapSize = 1000000;
 
@@ -94,6 +71,23 @@ Result Day11::Task2() {
 				gx += gapSize - 1;
 	}
 
+	return to_string(getDistanceSum(galaxies));
+}
+
+Day11::Universe Day11::parseUniverse() const {
+	Universe universe;
+
+	for (const string &line : input){
+		vector<bool> row(line.size(), false);
+		for (size_t index : findAll(line, "#"))
+			row[index] = true;
+		universe.push_back(row);
+	}
+
+	return universe;
+}
+
+uint64 Day11::getDistanceSum(const vector<Coord> &galaxies) {
 	uint64 sum = 0;
 
 	for (size_t i = 0; i < galaxies.size(); i++){
@@ -105,18 +99,15 @@ Result Day11::Task2() {
 		}
 	}
 
-	return to_string(sum);
+	return sum;
 }
 
-Day11::Universe Day11::parseUniverse() const {
-	Universe universe;
-
-	for (const string &line : input){
-		vector<bool> row(line.size(), false);
-		for (size_t index : findAll(line, "#"))
-			row[index] = true;
-		universe.push_back(row);
+vector<Day11::Coord> Day11::getGalaxies(const Day11::Universe &universe) {
+	vector<Coord> galaxies;
+	for (size_t y = 0; y < universe.size(); y++){
+		for (size_t x = 0; x < universe[y].size(); x++)
+			if (universe[y][x])
+				galaxies.emplace_back(x, y);
 	}
-
-	return universe;
+	return galaxies;
 }

src/days/11/Day11.h

@@ -6,6 +6,8 @@ class Day11 : public Day {
 	typedef pair<size_t, size_t> Coord;
 	typedef vector<vector<bool>> Universe;
 	Universe parseUniverse() const;
+	static vector<Coord> getGalaxies(const Universe &universe) ;
+	static uint64 getDistanceSum(const vector<Coord> &galaxies) ;
 protected:
 	Result Task1() override;
 

src/days/12/Day12.cpp

@@ -1,9 +1,105 @@
 #include "Day12.h"
 
 Result Day12::Task1() {
-	return Day::Task1();
+	uint64 sum = 0;
+
+	for (const auto& [conditions, groups] : parseRecords()){
+		uint64 localSum = 0;
+		auto arrangements = allArrangements({conditions, groups});
+		for (const auto& arrangement : arrangements){
+			if (matches(conditions, arrangement))
+				localSum++;
+
+		}
+		size_t count = arrangements.size();
+		sum += localSum;
+	}
+
+	return to_string(sum);
 }
 
 Result Day12::Task2() {
-	return Day::Task2();
+	uint64 sum = 0;
+
+	size_t index = 0;
+
+	for (auto& [conditions, groups] : parseRecords()){
+		auto condCopy = conditions;
+		auto groupsCopy = groups;
+		for (size_t i = 0; i < 4; i++){
+			conditions += "?" + condCopy;
+			groups.insert(groups.end(), groupsCopy.begin(), groupsCopy.end());
+		}
+		for (const auto& arrangement : allArrangements({conditions, groups})){
+			if (matches(conditions, arrangement))
+				sum++;
+		}
+
+
+		cout << index++ << endl;
+	}
+
+
+	return to_string(sum);
+}
+
+vector<Day12::Record> Day12::parseRecords() const {
+	vector<Record> records;
+
+	for (const string &line : input){
+		auto both = split(line, ' ');
+		records.emplace_back(both[0], parseUInts(both[1]));
+	}
+
+	return records;
+}
+
+vector<Day12::Arrangement> Day12::allArrangements(const Day12::Record &record) {
+	auto &[conditions, groups] = record;
+
+	vector<Arrangement> arrangements;
+
+	if (groups.size() == 1){
+		size_t group = groups[0];
+		for (size_t i = 0; i < conditions.size() - group + 1; i++){
+			Arrangement a(conditions.size(), false);
+			for (size_t j = 0; j < group; j++)
+				a[i + j] = true;
+			arrangements.push_back(a);
+		}
+
+		return arrangements;
+	}
+
+	vector<size_t> remainingGroups(groups.size() - 1);
+	std::copy(++groups.begin(), groups.end(), remainingGroups.begin());
+
+	size_t neededSpace = sum(remainingGroups) + remainingGroups.size() - 1;
+	size_t startLimit = conditions.size() - neededSpace - 1;
+
+	for (size_t i = groups[0] - 1; i < startLimit; i++){
+		Arrangement base(i + 2, true);
+		base.back() = false;
+		for (size_t j = 0; j < i - groups[0] + 1; j++)
+			base[j] = false;
+
+		auto addedRight = allArrangements({conditions.substr(i + 2), remainingGroups});
+		for (auto &a : addedRight){
+			Arrangement combined(base);
+			std::copy(a.begin(), a.end(), std::back_inserter(combined));
+			arrangements.push_back(combined);
+		}
+	}
+
+	return arrangements;
+}
+
+bool Day12::matches(const string &conditions, const Day12::Arrangement &arrangement) {
+	for (size_t i = 0; i < arrangement.size(); i++){
+		char cond = conditions[i];
+		bool broken = arrangement[i];
+		if (cond == '.' && broken || cond == '#' && !broken)
+			return false;
+	}
+	return true;
 }

src/days/12/Day12.h

@@ -3,6 +3,11 @@
 #include "../../Day.h"
 
 class Day12 : public Day {
+	typedef pair<string, vector<uint64>> Record;
+	typedef vector<bool> Arrangement;
+	vector<Record> parseRecords() const;
+	static vector<Arrangement> allArrangements(const Record &record);
+	static bool matches(const string& conditions, const Arrangement& arrangement);
 protected:
 	Result Task1() override;
 

src/util.h

@@ -32,3 +32,8 @@ bool isDigit(char c);
 
 vector<uint64> parseUInts(const string &data);
 vector<int64> parseInts(const string &data);
+
+template<typename T>
+T sum(const vector<T>& values){
+	return std::reduce(values.begin(), values.end(), T(), [](T a, T b){return a + b;});
+}