/in/foo.cc: In function 'long long int solveRow(const std::vector<int>&, int, int, int)':
/in/foo.cc:14:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |     if (k > row.size()) return 0; // 所有取数已完成
      |         ~~^~~~~~~~~~~~