AOC2023: Implement day11

userspace/aoc2023/CMakeLists.txt

@@ -13,6 +13,7 @@ set(AOC2023_PROJECTS
 	day8
 	day9
 	day10
+	day11
 )
 
 set(BANAN_AOC2023_BIN   ${BANAN_BIN}/aoc2023)

userspace/aoc2023/day11/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(aoc2023_day11 CXX)
+
+set(SOURCES
+	main.cpp
+)
+
+add_executable(aoc2023_day11 ${SOURCES})
+target_compile_options(aoc2023_day11 PUBLIC -O2 -g)
+target_link_libraries(aoc2023_day11 PUBLIC libc ban)
+
+add_dependencies(aoc2023_day11 libc-install ban-install)
+
+add_custom_target(aoc2023_day11-install
+	COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/aoc2023_day11 ${BANAN_AOC2023_BIN}/day11
+	DEPENDS aoc2023_day11
+	DEPENDS aoc2023_always
+)
+
+add_dependencies(aoc2023 aoc2023_day11)
+add_dependencies(aoc2023-install aoc2023_day11-install)

userspace/aoc2023/day11/main.cpp

@@ -0,0 +1,126 @@
+#include <BAN/Swap.h>
+#include <BAN/Vector.h>
+
+#include <inttypes.h>
+#include <stdio.h>
+
+using i8  = int8_t;
+using i16 = int16_t;
+using i32 = int32_t;
+using i64 = int64_t;
+
+using u8  = uint8_t;
+using u16 = uint16_t;
+using u32 = uint32_t;
+using u64 = uint64_t;
+
+using Map = BAN::Vector<BAN::Vector<u8>>;
+
+Map read_map(FILE* fp)
+{
+	Map result;
+
+	char buffer[256];
+	while (fgets(buffer, sizeof(buffer), fp))
+	{
+		const size_t len = strlen(buffer);
+		if (len < 2)
+			break;
+		MUST(result.emplace_back(len - 1));
+		for (size_t i = 0; i < len - 1; i++)
+			result.back()[i] = buffer[i];
+	}
+
+	return result;
+}
+
+i64 distance_with_expansion(const Map& map, u64 x1, u64 y1, u64 x2, u64 y2, u64 expansion_size)
+{
+	ASSERT(map[y1][x1] == '#');
+	ASSERT(map[y2][x2] == '#');
+
+	if (x2 < x1) BAN::swap(x1, x2);
+	if (y2 < y1) BAN::swap(y1, y2);
+
+	u64 expansion_count = 0;
+
+	for (u64 y = y1; y < y2; y++)
+	{
+		bool is_expanded = true;
+		for (u64 x = 0; x < map[0].size() && is_expanded; x++)
+			if (map[y][x] == '#')
+				is_expanded = false;
+		expansion_count += is_expanded;
+	}
+
+	for (u64 x = x1; x < x2; x++)
+	{
+		bool is_expanded = true;
+		for (u64 y = 0; y < map.size() && is_expanded; y++)
+			if (map[y][x] == '#')
+				is_expanded = false;
+		expansion_count += is_expanded;
+	}
+
+	return (x2 - x1) + (y2 - y1) + expansion_count * (expansion_size - 1);
+}
+
+i64 solution(FILE* fp, u64 expansion)
+{
+	auto map = read_map(fp);
+
+	i64 result = 0;
+
+	for (size_t i = 0; i < map.size() * map[0].size(); i++)
+	{
+		const u64 y1 = i / map[0].size();
+		const u64 x1 = i % map[0].size();
+		if (map[y1][x1] != '#')
+			continue;
+
+		for (size_t j = i + 1; j < map.size() * map[0].size(); j++)
+		{
+			const u64 y2 = j / map[0].size();
+			const u64 x2 = j % map[0].size();
+			if (map[y2][x2] != '#')
+				continue;
+			
+			result += distance_with_expansion(map, x1, y1, x2, y2, expansion);
+		}
+	}
+
+	return result;
+}
+
+i64 puzzle1(FILE* fp)
+{
+	return solution(fp, 2);
+}
+
+i64 puzzle2(FILE* fp)
+{
+	return solution(fp, 1'000'000);
+}
+
+int main(int argc, char** argv)
+{
+	const char* file_path = "/usr/share/aoc2023/day11_input.txt";
+
+	if (argc >= 2)
+		file_path = argv[1];
+
+	FILE* fp = fopen(file_path, "r");
+	if (fp == nullptr)
+	{
+		perror("fopen");
+		return 1;
+	}
+
+	printf("puzzle1: %" PRId64 "\n", puzzle1(fp));
+
+	fseek(fp, 0, SEEK_SET);
+
+	printf("puzzle2: %" PRId64 "\n", puzzle2(fp));
+
+	fclose(fp);
+}