Tried caching for part 2, still not fast enough

src/days/12/Day12.cpp

@@ -3,22 +3,17 @@
 Result Day12::Task1() {
 	uint64 sum = 0;
 
-	for (const auto& [conditions, groups] : parseRecords()){
-		uint64 localSum = 0;
-		auto arrangements = allArrangements({conditions, groups});
-		for (const auto& arrangement : arrangements){
+	for (const auto& [conditions, groups] : parseRecords())
+		for (const auto& arrangement : allArrangements({conditions, groups}))
 			if (matches(conditions, arrangement))
-				localSum++;
-
-		}
-		size_t count = arrangements.size();
-		sum += localSum;
-	}
+				sum++;
 
 	return to_string(sum);
 }
 
 Result Day12::Task2() {
+	arrangementsCache.clear();
+
 	uint64 sum = 0;
 
 	size_t index = 0;
@@ -35,7 +30,6 @@ Result Day12::Task2() {
 				sum++;
 		}
 
-
 		cout << index++ << endl;
 	}
 
@@ -56,6 +50,8 @@ vector<Day12::Record> Day12::parseRecords() const {
 
 vector<Day12::Arrangement> Day12::allArrangements(const Day12::Record &record) {
 	auto &[conditions, groups] = record;
+	if (arrangementsCache.contains({conditions.size(), groups}))
+		return arrangementsCache.at({conditions.size(), groups});
 
 	vector<Arrangement> arrangements;
 
@@ -68,6 +64,7 @@ vector<Day12::Arrangement> Day12::allArrangements(const Day12::Record &record) {
 			arrangements.push_back(a);
 		}
 
+		arrangementsCache[{conditions.size(), groups}] = arrangements;
 		return arrangements;
 	}
 
@@ -91,9 +88,12 @@ vector<Day12::Arrangement> Day12::allArrangements(const Day12::Record &record) {
 		}
 	}
 
+	arrangementsCache[{conditions.size(), groups}] = arrangements;
 	return arrangements;
 }
 
+std::unordered_map<pair<size_t, vector<size_t>>, vector<Day12::Arrangement>, Day12::RecordHash> Day12::arrangementsCache;
+
 bool Day12::matches(const string &conditions, const Day12::Arrangement &arrangement) {
 	for (size_t i = 0; i < arrangement.size(); i++){
 		char cond = conditions[i];
@@ -103,3 +103,7 @@ bool Day12::matches(const string &conditions, const Day12::Arrangement &arrangem
 	}
 	return true;
 }
+
+size_t Day12::RecordHash::operator ()(const pair<size_t, vector<uint64>> &record) const{
+	return sum(record.second) * record.first * record.second[0];
+}

src/days/12/Day12.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "../../Day.h"
+#include <unordered_map>
 
 class Day12 : public Day {
 	typedef pair<string, vector<uint64>> Record;
@@ -8,6 +9,11 @@ class Day12 : public Day {
 	vector<Record> parseRecords() const;
 	static vector<Arrangement> allArrangements(const Record &record);
 	static bool matches(const string& conditions, const Arrangement& arrangement);
+
+	struct RecordHash {
+		size_t operator ()(const pair<size_t, vector<uint64>> &record) const;
+	};
+	static std::unordered_map<pair<size_t, vector<size_t>>, vector<Arrangement>, RecordHash> arrangementsCache;
 protected:
 	Result Task1() override;