/in/foo.cc: In function 'void change_basis(int*, const int*, const StateSpace&, const StateSpace&)':
/in/foo.cc:193:13: warning: unused variable 'col' [-Wunused-variable]
  193 |         int col = active_list[i]; // 这里的active_list是src的？我们需要传入
      |             ^~~
/in/foo.cc:191:9: warning: unused variable 'map_idx' [-Wunused-variable]
  191 |     int map_idx[2005]; // 假设A不大
      |         ^~~~~~~