1 files changed, 55 insertions, 0 deletions

diff --git a/2024/25/day25a.cpp b/2024/25/day25a.cpp
new file mode 100644
index 0000000..22d8c15
--- /dev/null
+++ b/2024/25/day25a.cpp
@@ -0,0 +1,55 @@
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+#include <map>
+#include <queue>
+#include <ranges>
+#include <set>
+#include <sstream>
+#include <string>
+#include <string_view>
+#include <vector>
+using namespace std;
+
+class KeyLock {
+public:
+        KeyLock() { fill(a, a+5, 0); }
+
+        void addrow(const string& s) {
+                for (int i = 0; i < 5; i++)
+                        a[i] += s[i] == '#';
+        }
+
+        bool operator&(const KeyLock& other) const {
+                for (int i = 0; i < 5; i++)
+                        if (a[i] + other.a[i] > 5)
+                                return false;
+                return true;
+        }
+private:
+        int a[5];
+};
+
+int main() {
+        vector<KeyLock> keys, locks;
+        string line;
+        while (getline(cin, line)) {
+                KeyLock k;
+                bool key = line[0] == '.';
+                for (int i = 0; i < 5; i++) {
+                        getline(cin, line);
+                        k.addrow(line);
+                }
+                if (key) keys.push_back(k);
+                else locks.push_back(k);
+                getline(cin, line);
+                getline(cin, line);
+        }
+
+        int tot = 0;
+        for (auto k : keys)
+                for (auto l : locks)
+                        tot += (k & l) ? 1 : 0;
+        cout << tot << endl;
+        return 0;
+}