From 19b1f4d145b62da1292e5aef93cb9032f764b5ac Mon Sep 17 00:00:00 2001
From: Benjamin Kraft <benjamin.kraft@online.de>
Date: Thu, 21 Dec 2023 15:35:27 +0100
Subject: [PATCH] Day 12 Task 1

---
 src/days/12/Day12.cpp | 97 +++++++++++++++++++++++++++++++++++++++++--
 src/days/12/Day12.h   |  4 ++
 src/util.h            |  7 +++-
 3 files changed, 104 insertions(+), 4 deletions(-)

diff --git a/src/days/12/Day12.cpp b/src/days/12/Day12.cpp
index fd9f16d..cf84bc7 100644
--- a/src/days/12/Day12.cpp
+++ b/src/days/12/Day12.cpp
@@ -1,9 +1,100 @@
 #include "Day12.h"
 
 Result Day12::Task1() {
-	return Day::Task1();
+	uint64 sum = 0;
+
+	for (const auto& [conditions, groups] : parseRecords()){
+		for (const auto& arrangement : allArrangements({conditions, groups})){
+			bool possible = true;
+			for (size_t i = 0; i < arrangement.size(); i++){
+				char cond = conditions[i];
+				bool broken = arrangement[i];
+				if (cond == '.' && broken || cond == '#' && !broken){
+					possible = false;
+					break;
+				}
+			}
+			if (possible)
+				sum++;
+		}
+	}
+
+	return to_string(sum);
 }
 
 Result Day12::Task2() {
-	return Day::Task2();
-}
\ No newline at end of file
+
+
+
+	uint64 sum = 0;
+
+	for (auto[conditions, groups] : parseRecords()){
+
+		for (const auto& arrangement : allArrangements({conditions, groups})){
+			bool possible = true;
+			for (size_t i = 0; i < arrangement.size(); i++){
+				char cond = conditions[i];
+				bool broken = arrangement[i];
+				if (cond == '.' && broken || cond == '#' && !broken){
+					possible = false;
+					break;
+				}
+			}
+			if (possible)
+				sum++;
+		}
+	}
+
+	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;
+}
diff --git a/src/days/12/Day12.h b/src/days/12/Day12.h
index 1d4054d..d24bff4 100644
--- a/src/days/12/Day12.h
+++ b/src/days/12/Day12.h
@@ -3,6 +3,10 @@
 #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);
 protected:
 	Result Task1() override;
 
diff --git a/src/util.h b/src/util.h
index 6d3a59c..924fc54 100644
--- a/src/util.h
+++ b/src/util.h
@@ -31,4 +31,9 @@ bool isDigit(char c, uint8_t &result);
 bool isDigit(char c);
 
 vector<uint64> parseUInts(const string &data);
-vector<int64> parseInts(const string &data);
\ No newline at end of file
+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;});
+}
\ No newline at end of file