From 12ba4504a7bbf3449552e37e8f28920e95b890c0 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Mon, 23 Dec 2024 10:47:46 +0100
Subject: aoc 2024, day 23, part 1

---
 2024/src/day23.cpp | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 2024/src/day23.cpp

(limited to '2024/src')

diff --git a/2024/src/day23.cpp b/2024/src/day23.cpp
new file mode 100644
index 0000000..45d6d28
--- /dev/null
+++ b/2024/src/day23.cpp
@@ -0,0 +1,65 @@
+#include <fstream>
+#include <iostream>
+#include <map>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+using namespace std;
+
+vector<string>
+split(const string& line, char sep = ' ')
+{
+	vector<string> parts;
+	stringstream   input{ line };
+
+	for ( string part; getline(input, part, sep); ) {
+		parts.emplace_back(part);
+	}
+
+	return parts;
+}
+
+map<string, set<string>>
+read_file(string_view filename)
+{
+	fstream                  input{ filename };
+	map<string, set<string>> data;
+
+	for ( string line; getline(input, line); ) {
+		const auto  parts = split(line, '-');
+		const auto& lhs   = parts[0];
+		const auto& rhs   = parts[1];
+		data[lhs].insert(rhs);
+		data[rhs].insert(lhs);
+	}
+
+	return data;
+}
+
+void
+part1(const map<string, set<string>>& nodes)
+{
+	set<set<string>> connected;
+
+	for ( const auto& [node0, links]: nodes ) {
+		for ( const auto& node1: links ) {
+			for ( const auto& node2: nodes.at(node1) ) {
+				if ( node0 != node2 and nodes.at(node2).contains(node0) ) {
+					if ( node0.starts_with('t') || node1.starts_with('t') || node2.starts_with('t') ) {
+						connected.insert({ node0, node1, node2 });
+					}
+				}
+			}
+		}
+	}
+
+	cout << connected.size() << endl;
+}
+
+int
+main()
+{
+	auto data = read_file("data/day23.txt");
+	part1(data);
+}
-- 
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