remove unnecessary std prefix

main.cpp

@@ -64,7 +64,7 @@ Moves serialize(const string &s) {
         if (player == "END") break;
         if (!isValidPlayer(player[0])) {
             string err = "Invalid player: " + player;
-            throw std::invalid_argument(err);
+            throw invalid_argument(err);
         }
         result.moves.push_back({player[0], x, y});
     }
@@ -259,7 +259,7 @@ int main(int argc, char **argv) {
 
     try {
         return init(argv[1]);
-    } catch (const std::invalid_argument &e) {
+    } catch (const invalid_argument &e) {
         cerr << e.what() << nl;
         return 1;
     }