From c90d2383059cc69c5fdd5da94e91dd28dab09bb3 Mon Sep 17 00:00:00 2001
From: Benjamin Kraft <benjamin.kraft@online.de>
Date: Wed, 20 Dec 2023 16:09:37 +0100
Subject: [PATCH] Day 11

---
 src/days/11/Day11.cpp | 119 ++++++++++++++++++++++++++++++++++++++++--
 src/days/11/Day11.h   |   3 ++
 2 files changed, 119 insertions(+), 3 deletions(-)

diff --git a/src/days/11/Day11.cpp b/src/days/11/Day11.cpp
index 8376f31..515e743 100644
--- a/src/days/11/Day11.cpp
+++ b/src/days/11/Day11.cpp
@@ -1,9 +1,122 @@
 #include "Day11.h"
 
 Result Day11::Task1() {
-	return Day::Task1();
+	Universe universe = parseUniverse();
+
+	// expand vertically
+	for (size_t y = 0; y < universe.size(); y++){
+		auto row = universe[y];
+		if (!*std::max_element(row.begin(), row.end())){
+			y++;
+			auto iter = universe.begin();
+			std::advance(iter, y);
+			universe.insert(iter, vector<bool>(row.size()));
+		}
+	}
+
+	// expand horizontally
+	for (size_t x = 0; x < universe[0].size(); x++){
+		bool galaxyFound = false;
+		for (auto &row : universe)
+			galaxyFound = std::max(galaxyFound, bool(row[x]));
+		if (!galaxyFound){
+			x++;
+			for (auto &row : universe){
+				auto iter = row.begin();
+				std::advance(iter, x);
+				row.insert(iter, false);
+			}
+		}
+	}
+
+	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];
+
+			sum += std::abs(long(x2 - x1)) + std::abs(long(y2 - y1));
+		}
+	}
+
+	return to_string(sum);
 }
 
 Result Day11::Task2() {
-	return Day::Task2();
-}
\ No newline at end of file
+	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);
+	}
+
+	const size_t gapSize = 1000000;
+
+	// expand vertically
+	vector<size_t> rowExpansions;
+	for (size_t y = 0; y < universe.size(); y++){
+		auto row = universe[y];
+		if (!*std::max_element(row.begin(), row.end()))
+			rowExpansions.push_back(y);
+	}
+	std::reverse(rowExpansions.begin(), rowExpansions.end());
+	for (size_t y : rowExpansions){
+		for (auto &[gx, gy] : galaxies)
+			if (gy > y)
+				gy += gapSize - 1;
+	}
+
+	// expand horizontally
+	vector<size_t> columnExpansions;
+	for (size_t x = 0; x < universe[0].size(); x++){
+		bool galaxyFound = false;
+		for (auto &row : universe)
+			galaxyFound = std::max(galaxyFound, bool(row[x]));
+		if (!galaxyFound)
+			columnExpansions.push_back(x);
+	}
+	std::reverse(columnExpansions.begin(), columnExpansions.end());
+	for (size_t x : columnExpansions){
+		for (auto &[gx, gy] : galaxies)
+			if (gx > x)
+				gx += gapSize - 1;
+	}
+
+	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];
+
+			sum += std::abs(long(x2 - x1)) + std::abs(long(y2 - y1));
+		}
+	}
+
+	return to_string(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);
+	}
+
+	return universe;
+}
diff --git a/src/days/11/Day11.h b/src/days/11/Day11.h
index 29ebeba..c37e70a 100644
--- a/src/days/11/Day11.h
+++ b/src/days/11/Day11.h
@@ -3,6 +3,9 @@
 #include "../../Day.h"
 
 class Day11 : public Day {
+	typedef pair<size_t, size_t> Coord;
+	typedef vector<vector<bool>> Universe;
+	Universe parseUniverse() const;
 protected:
 	Result Task1() override;