aoc 2024, day 23, part 1

1 files changed, 65 insertions, 0 deletions

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);
+}