aoc2024: Implement day10 solution

Base sysroot is not only installed when creating the syroot directory
for the first time. To get it installed again, you have to either delete
the old sysroot diretory or run clean target

This makes it so its actually possible to edit files specified in the
base sysroot without random hacks.

CMakeLists.txt

@@ -6,8 +6,6 @@ endif ()
 
 project(banan-os CXX C ASM)
 
-set(BANAN_BASE_SYSROOT ${CMAKE_SOURCE_DIR}/base-sysroot.tar.gz)
-
 set(BANAN_INCLUDE ${BANAN_SYSROOT}/usr/include)
 set(BANAN_LIB     ${BANAN_SYSROOT}/usr/lib)
 set(BANAN_BIN     ${BANAN_SYSROOT}/usr/bin)
@@ -57,8 +55,3 @@ add_subdirectory(kernel)
 add_subdirectory(bootloader)
 add_subdirectory(BAN)
 add_subdirectory(userspace)
-
-add_custom_target(sysroot
-	COMMAND ${CMAKE_COMMAND} -E make_directory ${BANAN_SYSROOT}
-	COMMAND cd ${BANAN_SYSROOT} && tar xf ${BANAN_BASE_SYSROOT}
-)

script/build.sh

@@ -66,6 +66,14 @@ run_bochs () {
 	$BANAN_SCRIPT_DIR/bochs.sh $@
 }
 
+if [ ! -d $BANAN_SYSROOT ]; then
+	mkdir -p $BANAN_SYSROOT
+
+	pushd $BANAN_SYSROOT
+	run_fakeroot tar xf ${BANAN_ROOT_DIR}/base-sysroot.tar.gz
+	popd
+fi
+
 if [ -v QEMU_ACCEL ]; then
 	:
 elif type kvm-ok &> /dev/null; then

userspace/aoc2024/CMakeLists.txt

@@ -7,6 +7,8 @@ set(AOC2024_PROJECTS
 	day6
 	day7
 	day8
+	day9
+	day10
 	full
 )
 

userspace/aoc2024/day10/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(aoc2024_day10 ${SOURCES})
+banan_include_headers(aoc2024_day10 ban)
+banan_link_library(aoc2024_day10 libc)
+
+install(TARGETS aoc2024_day10 OPTIONAL)

userspace/aoc2024/day10/main.cpp

@@ -0,0 +1,171 @@
+#include <BAN/HashSet.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 isize = ssize_t;
+
+using u8  = uint8_t;
+using u16 = uint16_t;
+using u32 = uint32_t;
+using u64 = uint64_t;
+using usize = size_t;
+
+struct Position
+{
+	u32 x, y;
+
+	constexpr bool operator==(const Position& other) const
+	{
+		return x == other.x && y == other.y;
+	}
+};
+
+struct PositionHash
+{
+	constexpr BAN::hash_t operator()(Position state) const
+	{
+		return BAN::hash<u64>{}((u64)state.x << 32 | (u64)state.y);
+	}
+};
+
+struct Grid2D
+{
+	usize width { 0 };
+	usize height { 0 };
+	BAN::Vector<char> data;
+
+	inline char get(usize x, usize y) const
+	{
+		ASSERT(x < width && y < height);
+		return data[y * width + x];
+	}
+};
+
+static Grid2D read_grid2d(FILE* fp)
+{
+	usize width { 0 };
+	usize height { 0 };
+	BAN::Vector<char> data;
+
+	char buffer[1024];
+	while (fgets(buffer, sizeof(buffer), fp))
+	{
+		const usize len = strlen(buffer);
+		if (len == 0 || buffer[0] == '\n')
+			break;
+		if (data.empty())
+			width = len - 1;
+		height++;
+
+		ASSERT(buffer[width] == '\n');
+
+		if (data.capacity() < height * width)
+			MUST(data.reserve(2 * height * width));
+
+		MUST(data.resize(height * width));
+		memcpy(&data[(height - 1) * width], buffer, width);
+	}
+
+	(void)data.shrink_to_fit();
+
+	return Grid2D {
+		.width = width,
+		.height = height,
+		.data = BAN::move(data),
+	};
+}
+
+i64 get_trailhead_score(const Grid2D& map, u32 x, u32 y, char curr, BAN::HashSet<Position, PositionHash>& trail_ends, bool allow_duplicate)
+{
+	if (x >= map.width)
+		return 0;
+	if (y >= map.height)
+		return 0;
+
+	if (map.get(x, y) != curr)
+		return 0;
+	if (curr == '9')
+	{
+		const auto pos = Position { .x = x, .y = y };
+		if (trail_ends.contains(pos))
+			return allow_duplicate;
+		MUST(trail_ends.insert(Position { .x = x, .y = y }));
+		return 1;
+	}
+
+	i64 result = 0;
+	result += get_trailhead_score(map, x - 1, y,     curr + 1, trail_ends, allow_duplicate);
+	result += get_trailhead_score(map, x,     y - 1, curr + 1, trail_ends, allow_duplicate);
+	result += get_trailhead_score(map, x + 1, y,     curr + 1, trail_ends, allow_duplicate);
+	result += get_trailhead_score(map, x,     y + 1, curr + 1, trail_ends, allow_duplicate);
+	return result;
+}
+
+i64 part1(FILE* fp)
+{
+	auto map = read_grid2d(fp);
+
+	i64 result = 0;
+
+	for (u32 y = 0; y < map.height; y++)
+	{
+		for (u32 x = 0; x < map.width; x++)
+		{
+			if (map.get(x, y) != '0')
+				continue;
+			BAN::HashSet<Position, PositionHash> trail_ends;
+			result += get_trailhead_score(map, x, y, '0', trail_ends, false);
+		}
+	}
+
+	return result;
+}
+
+i64 part2(FILE* fp)
+{
+	auto map = read_grid2d(fp);
+
+	i64 result = 0;
+
+	for (u32 y = 0; y < map.height; y++)
+	{
+		for (u32 x = 0; x < map.width; x++)
+		{
+			if (map.get(x, y) != '0')
+				continue;
+			BAN::HashSet<Position, PositionHash> trail_ends;
+			result += get_trailhead_score(map, x, y, '0', trail_ends, true);
+		}
+	}
+
+	return result;
+}
+
+int main(int argc, char** argv)
+{
+	const char* file_path = "/usr/share/aoc2024/day10_input.txt";
+
+	if (argc >= 2)
+		file_path = argv[1];
+
+	FILE* fp = fopen(file_path, "r");
+	if (fp == nullptr)
+	{
+		perror("fopen");
+		return 1;
+	}
+
+	printf("part1: %" PRId64 "\n", part1(fp));
+
+	fseek(fp, 0, SEEK_SET);
+
+	printf("part2: %" PRId64 "\n", part2(fp));
+
+	fclose(fp);
+}

userspace/aoc2024/day9/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(aoc2024_day9 ${SOURCES})
+banan_include_headers(aoc2024_day9 ban)
+banan_link_library(aoc2024_day9 libc)
+
+install(TARGETS aoc2024_day9 OPTIONAL)

userspace/aoc2024/day9/main.cpp

@@ -0,0 +1,153 @@
+#include <BAN/Vector.h>
+
+#include <ctype.h>
+#include <inttypes.h>
+#include <stdio.h>
+
+using i8  = int8_t;
+using i16 = int16_t;
+using i32 = int32_t;
+using i64 = int64_t;
+using isize = ssize_t;
+
+using u8  = uint8_t;
+using u16 = uint16_t;
+using u32 = uint32_t;
+using u64 = uint64_t;
+using usize = size_t;
+
+static BAN::Vector<u32> parse_input(FILE* fp)
+{
+	BAN::Vector<u32> result;
+
+	u32 idx = 0;
+
+	char buffer[1024];
+	while (fgets(buffer, sizeof(buffer), fp))
+	{
+		usize len = strlen(buffer);
+		if (len > 0 && buffer[len - 1] == '\n')
+			len--;
+
+		for (usize i = 0; i < len; i++)
+		{
+			const u32 block_id = (idx % 2) ? 0xFFFFFFFF : idx / 2;
+
+			ASSERT(isdigit(buffer[i]));
+			for (i8 j = 0; j < buffer[i] - '0'; j++)
+				MUST(result.push_back(block_id));
+
+			idx++;
+		}
+	}
+
+	return result;
+}
+
+i64 part1(FILE* fp)
+{
+	auto input = parse_input(fp);
+
+	usize l = 0;
+	usize r = input.size() - 1;
+
+	i64 result = 0;
+
+	while (l <= r)
+	{
+		if (input[l] != 0xFFFFFFFF)
+		{
+			result += input[l] * l;
+			l++;
+			continue;
+		}
+
+		while (l < r && input[r] == 0xFFFFFFFF)
+			r--;
+
+		if (l == r)
+			continue;
+
+		result += input[r] * l;
+		r--;
+		l++;
+	}
+
+	return result;
+}
+
+i64 part2(FILE* fp)
+{
+	auto input = parse_input(fp);
+
+	for (usize r = input.size(); r > 0;)
+	{
+		if (input[r - 1] == 0xFFFFFFFF)
+		{
+			r--;
+			continue;
+		}
+
+		const u32 id = input[r - 1];
+
+		usize rlen = 0;
+		while (r - rlen - 1 > 0 && input[r - rlen - 1] == id)
+			rlen++;
+
+		usize l = 0;
+		for (; l < r - rlen; l++)
+		{
+			if (input[l] != 0xFFFFFFFF)
+				continue;
+
+			usize llen = 1;
+			while (llen < rlen && input[l + llen] == 0xFFFFFFFF)
+				llen++;
+
+			if (llen == rlen)
+				break;
+		}
+
+		if (l < r - rlen)
+		{
+			for (usize i = 0; i < rlen; i++)
+				input[r - i - 1] = 0xFFFFFFFF;
+			for (usize i = 0; i < rlen; i++)
+				input[l + i] = id;
+		}
+
+		r -= rlen;
+		while (r > 0 && input[r - 1] == id)
+			r--;
+	}
+
+	i64 result = 0;
+	for (usize i = 0; i < input.size(); i++)
+		if (input[i] != 0xFFFFFFFF)
+			result += i * input[i];
+
+	return result;
+}
+
+int main(int argc, char** argv)
+{
+	const char* file_path = "/usr/share/aoc2024/day9_input.txt";
+
+	if (argc >= 2)
+		file_path = argv[1];
+
+	FILE* fp = fopen(file_path, "r");
+	if (fp == nullptr)
+	{
+		perror("fopen");
+		return 1;
+	}
+
+	printf("part1: %" PRId64 "\n", part1(fp));
+
+	fseek(fp, 0, SEEK_SET);
+
+	printf("part2: %" PRId64 "\n", part2(fp));
+
+	fclose(fp);
+}

userspace/libraries/LibC/CMakeLists.txt

@@ -58,7 +58,6 @@ target_compile_options(objlibc PUBLIC -Wall -Wextra -Werror -Wno-error=stack-usa
 function(add_crtx crtx)
 	add_custom_target(${crtx}
 		COMMAND ${CMAKE_CXX_COMPILER} -c -o ${CMAKE_INSTALL_LIBDIR}/${crtx}.o ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/${crtx}.S
-		DEPENDS sysroot
 	)
 	add_dependencies(objlibc ${crtx})
 endfunction()