aoc2025: Implement day6 solution

userspace/aoc2025/CMakeLists.txt

@@ -4,6 +4,7 @@ set(AOC2025_PROJECTS
 	day3
 	day4
 	day5
+	day6
 	full
 )
 

userspace/aoc2025/day6/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(aoc2025_day6 ${SOURCES})
+banan_include_headers(aoc2025_day6 ban)
+banan_link_library(aoc2025_day6 libc)
+
+install(TARGETS aoc2025_day6 OPTIONAL)

userspace/aoc2025/day6/main.cpp

@@ -0,0 +1,152 @@
+#include <BAN/String.h>
+#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 u8  = uint8_t;
+using u16 = uint16_t;
+using u32 = uint32_t;
+using u64 = uint64_t;
+
+i64 part1(FILE* fp)
+{
+	struct Operation
+	{
+		BAN::Vector<i64> values;
+		char op;
+	};
+
+	BAN::Vector<Operation> operations;
+
+	BAN::String line;
+	char line_buffer[128];
+	while (fgets(line_buffer, sizeof(line_buffer), fp))
+	{
+		MUST(line.append(line_buffer));
+		if (line.back() != '\n')
+			continue;
+		line.pop_back();
+
+		auto parts = MUST(line.sv().split(' '));
+		if (operations.size() < parts.size())
+			MUST(operations.resize(parts.size()));
+
+		if (isdigit(parts[0][0]))
+		{
+			for (size_t i = 0; i < parts.size(); i++)
+				MUST(operations[i].values.push_back(atoll(parts[i].data())));
+			line.clear();
+		}
+		else
+		{
+			for (size_t i = 0; i < parts.size(); i++)
+				operations[i].op = parts[i][0];
+			break;
+		}
+	}
+
+	i64 result = 0;
+
+	for (const auto& operation : operations)
+	{
+		i64 value;
+		switch (operation.op)
+		{
+			case '+':
+				value = 0;
+				for (auto val : operation.values)
+					value += val;
+				break;
+			case '*':
+				value = 1;
+				for (auto val : operation.values)
+					value *= val;
+				break;
+			default:
+				ASSERT_NOT_REACHED();
+		}
+		result += value;
+	}
+
+	return result;
+}
+
+i64 part2(FILE* fp)
+{
+	BAN::Vector<BAN::String> lines;
+	MUST(lines.emplace_back());
+
+	char line_buffer[128];
+	while (fgets(line_buffer, sizeof(line_buffer), fp))
+	{
+		MUST(lines.back().append(line_buffer));
+		if (lines.back().back() != '\n')
+			continue;
+		lines.back().pop_back();
+		MUST(lines.emplace_back());
+	}
+
+	while (lines.back().empty())
+		lines.pop_back();
+
+	i64 result = 0;
+
+	char op = 0;
+	i64 current = 0;
+	for (size_t i = 0; i < lines.front().size(); i++)
+	{
+		if (lines.back()[i] != ' ')
+		{
+			result += current;
+
+			op = lines.back()[i];
+			current = (op == '+') ? 0 : 1;
+		}
+
+		i64 value = 0;
+		bool all_space = true;
+		for (size_t j = 0; j < lines.size() - 1; j++)
+		{
+			if (isdigit(lines[j][i]))
+				value = (value * 10) + (lines[j][i] - '0');
+			all_space = all_space && lines[j][i] == ' ';
+		}
+
+		if (all_space)
+			continue;
+
+		current = (op == '+') ? current + value : current * value;
+	}
+
+	return result + current;
+}
+
+int main(int argc, char** argv)
+{
+	const char* file_path = "/usr/share/aoc2025/day6_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);
+}