From ccb603d77fe2f66d79508cbcfa94558d5b770bbc Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Thu, 5 Dec 2024 08:16:34 +0200
Subject: [PATCH] aoc2024: Implement day5 solution

---
 userspace/aoc2024/CMakeLists.txt      |   1 +
 userspace/aoc2024/day5/CMakeLists.txt |   9 +++
 userspace/aoc2024/day5/main.cpp       | 109 ++++++++++++++++++++++++++
 3 files changed, 119 insertions(+)
 create mode 100644 userspace/aoc2024/day5/CMakeLists.txt
 create mode 100644 userspace/aoc2024/day5/main.cpp

diff --git a/userspace/aoc2024/CMakeLists.txt b/userspace/aoc2024/CMakeLists.txt
index 0300c639..4721973f 100644
--- a/userspace/aoc2024/CMakeLists.txt
+++ b/userspace/aoc2024/CMakeLists.txt
@@ -3,6 +3,7 @@ set(AOC2024_PROJECTS
 	day2
 	day3
 	day4
+	day5
 	full
 )
 
diff --git a/userspace/aoc2024/day5/CMakeLists.txt b/userspace/aoc2024/day5/CMakeLists.txt
new file mode 100644
index 00000000..c361c6cb
--- /dev/null
+++ b/userspace/aoc2024/day5/CMakeLists.txt
@@ -0,0 +1,9 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(aoc2024_day5 ${SOURCES})
+banan_include_headers(aoc2024_day5 ban)
+banan_link_library(aoc2024_day5 libc)
+
+install(TARGETS aoc2024_day5 OPTIONAL)
diff --git a/userspace/aoc2024/day5/main.cpp b/userspace/aoc2024/day5/main.cpp
new file mode 100644
index 00000000..66ce9304
--- /dev/null
+++ b/userspace/aoc2024/day5/main.cpp
@@ -0,0 +1,109 @@
+#include <BAN/Array.h>
+#include <BAN/Vector.h>
+#include <BAN/StringView.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 u8  = uint8_t;
+using u16 = uint16_t;
+using u32 = uint32_t;
+using u64 = uint64_t;
+
+i64 part1(FILE* fp)
+{
+	bool requirements[100][100] {};
+	char buffer[128];
+
+	int a, b;
+	while (fgets(buffer, sizeof(buffer), fp) && sscanf(buffer, "%d|%d", &a, &b) == 2)
+		requirements[b][a] = true;
+
+	i64 result = 0;
+
+	while (fgets(buffer, sizeof(buffer), fp))
+	{
+		BAN::Vector<int> update;
+		for (size_t i = 0; isdigit(buffer[i]); i += 3)
+			MUST(update.push_back(atoi(&buffer[i])));
+
+		bool valid = true;
+		for (size_t i = 0; i < update.size() && valid; i++)
+			for (size_t j = i + 1; j < update.size() && valid; j++)
+				if (requirements[update[i]][update[j]])
+					valid = false;
+
+		if (valid)
+			result += update[update.size() / 2];
+	}
+
+	return result;
+}
+
+i64 part2(FILE* fp)
+{
+	bool requirements[100][100] {};
+	char buffer[128];
+
+	int a, b;
+	while (fgets(buffer, sizeof(buffer), fp) && sscanf(buffer, "%d|%d", &a, &b) == 2)
+		requirements[b][a] = true;
+
+	i64 result = 0;
+
+	while (fgets(buffer, sizeof(buffer), fp))
+	{
+		BAN::Vector<int> update;
+		for (size_t i = 0; isdigit(buffer[i]); i += 3)
+			MUST(update.push_back(atoi(&buffer[i])));
+
+		bool correct { true };
+		for (size_t i = 0; i < update.size(); i++)
+		{
+			for (size_t j = i + 1; j < update.size(); j++)
+			{
+				if (requirements[update[i]][update[j]])
+				{
+					BAN::swap(update[i], update[j]);
+					correct = false;
+					i--;
+					break;
+				}
+			}
+		}
+
+		if (!correct)
+			result += update[update.size() / 2];
+	}
+
+	return result;
+}
+
+int main(int argc, char** argv)
+{
+	const char* file_path = "/usr/share/aoc2024/day5_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);
+}