From 4b6c1b0e539d9fc37b646af5865b75aaa5b49bfc Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Wed, 13 Nov 2024 22:20:30 +0100
Subject: aoc 2015, days 5, 6 and 7

---
 2015/src/day07.cpp | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 2015/src/day07.cpp

(limited to '2015/src/day07.cpp')

diff --git a/2015/src/day07.cpp b/2015/src/day07.cpp
new file mode 100644
index 0000000..f24d5af
--- /dev/null
+++ b/2015/src/day07.cpp
@@ -0,0 +1,97 @@
+#include <cinttypes>
+#include <cstdio>
+#include <fstream>
+#include <iostream>
+#include <map>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+auto
+read_file(string_view filename)
+{
+	fstream             input{ filename };
+	map<string, string> deps;
+
+	for ( string line; getline(input, line); ) {
+		const auto pos = line.find(" -> ");
+		if ( pos == string::npos ) {
+			continue;
+		}
+
+		deps[line.substr(pos + 4)] = line.substr(0, pos);
+	}
+
+	return deps;
+}
+
+// NOLINTBEGIN
+uint16_t
+solve(map<string, string>& deps, const string& dep)
+{
+	map<string, uint16_t> cache;
+
+	function<uint16_t(const string&)> solve = [&](const string& dep) -> uint16_t {
+		if (cache.contains(dep)) {
+			return cache[dep];
+		}
+
+		uint16_t value = 0;
+		if (sscanf(dep.c_str(), "%" SCNu16, &value) == 1) {
+			return cache[dep] = value;
+		}
+
+		const auto& line = deps[dep];
+
+		static const size_t MAX = 11;
+		char lhs[MAX], rhs[MAX];
+
+		if ( sscanf(line.c_str(), "%10s AND %10s", lhs, rhs) == 2 ) {
+			value = solve(lhs) & solve(rhs);
+		}
+		else if ( sscanf(line.c_str(), "%10s OR %10s", lhs, rhs) == 2 ) {
+			value = solve(lhs) | solve(rhs);
+		}
+		else if ( sscanf(line.c_str(), "%10s LSHIFT %10s", lhs, rhs) == 2 ) {
+			value = static_cast<uint16_t>(solve(lhs) << solve(rhs));
+		}
+		else if ( sscanf(line.c_str(), "%10s RSHIFT %10s", lhs, rhs) == 2 ) {
+			value = static_cast<uint16_t>(solve(lhs) >> solve(rhs));
+		}
+		else if ( sscanf(line.c_str(), "NOT %10s", lhs) == 1 ) {
+			value = ~solve(lhs);
+		}
+		else {
+			value = solve(line);
+		}
+
+		return cache[dep] = value;
+	};
+
+	return solve(dep);
+}
+// NOLINTEND
+
+auto
+part1(map<string, string>& deps)
+{
+	auto result = solve(deps, "a");
+	cout << result << endl;
+	return result;
+}
+
+void
+part2(map<string, string>& deps, uint16_t result)
+{
+	deps["b"] = to_string(result);
+	cout << solve(deps, "a") << endl;
+}
+
+int
+main()
+{
+	auto deps = read_file("data/day07.txt");
+	auto result = part1(deps);
+	part2(deps, result);
+}
-- 
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