2024 day 23

2024/23/main-1.cpp

@@ -0,0 +1,39 @@
+#include "../../include/aoc.hpp"
+#include <bits/stdc++.h>
+using namespace std;
+
+int main() {
+	ios::sync_with_stdio(0);
+	cin.tie(0);
+
+	unordered_set<string> all;
+	unordered_map<string, unordered_set<string>> m;
+
+	string line;
+	while (getline(cin, line)) {
+		string a = line.substr(0, 2);
+		string b = line.substr(3, 5);
+		all.insert(a);
+		all.insert(b);
+		m[a].insert(b);
+		m[b].insert(a);
+	}
+
+	int count = 0;
+	vector<string> vm;
+	vm.assign(all.begin(), all.end());
+	for (int i = 2; i < vm.size(); i++) {
+		for (int j = 1; j < i; j++) {
+			for (int k = 0; k < j; k++) {
+				const string &a = vm[i], &b = vm[j], &c = vm[k];
+				if (a[0] != 't' && b[0] != 't' && c[0] != 't') {
+					continue;
+				}
+				if (m[a].contains(b) && m[b].contains(c) && m[c].contains(a)) {
+					count++;
+				}
+			}
+		}
+	}
+	cout << count << '\n';
+}

2024/23/main-2.cpp

@@ -0,0 +1,72 @@
+#include "../../include/aoc.hpp"
+#include <bits/stdc++.h>
+using namespace std;
+
+typedef vector<string> vs;
+
+unordered_map<string, unordered_set<string>> m;
+vector<vs> found;
+
+void rec(vs yes, vs maybe, vs no) {
+	if (maybe.empty() && no.empty()) {
+		found.push_back(yes);
+		return;
+	}
+
+	while (!maybe.empty()) {
+		string s = maybe.back();
+		vs tyes = yes;
+		tyes.push_back(s);
+		vs tmaybe;
+		for (string ss : maybe) {
+			if (m[s].contains(ss)) {
+				tmaybe.push_back(ss);
+			}
+		}
+		vs tno;
+		for (string ss : no) {
+			if (m[s].contains(ss)) {
+				tno.push_back(ss);
+			}
+		}
+		rec(tyes, tmaybe, tno);
+		maybe.pop_back();
+		no.push_back(s);
+	}
+}
+
+int main() {
+	ios::sync_with_stdio(0);
+	cin.tie(0);
+
+	unordered_set<string> all;
+
+	string line;
+	while (getline(cin, line)) {
+		string a = line.substr(0, 2);
+		string b = line.substr(3, 5);
+		all.insert(a);
+		all.insert(b);
+		m[a].insert(b);
+		m[b].insert(a);
+	}
+
+	vs vm;
+	vm.assign(all.begin(), all.end());
+	rec({}, vm, {});
+
+	vs *ms = nullptr;
+	for (auto &c : found) {
+		if (ms == nullptr || ms->size() < c.size()) {
+			ms = &c;
+		}
+	}
+	vs &msr = *ms;
+
+	sort(msr.begin(), msr.end());
+	cout << msr[0];
+	for (int i = 1; i < msr.size(); i++) {
+		cout << ',' << msr[i];
+	}
+	cout << '\n';
+}