In file included from /in/Compile/check.cpp:7:
/in/sokoban.hpp:44:30: error: implicit conversion changes signedness: 'int' to 'unsigned long' [-Werror,-Wsign-conversion]
    int x = static_cast<int>(pos / cols);
                             ^~~ ~
/in/sokoban.hpp:45:30: error: implicit conversion changes signedness: 'int' to 'unsigned long' [-Werror,-Wsign-conversion]
    int y = static_cast<int>(pos % cols);
                             ^~~ ~
/in/sokoban.hpp:156:60: error: implicit conversion changes signedness: 'int' to 'std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::size_type' (aka 'unsigned long') [-Werror,-Wsign-conversion]
                q.emplace(new_pos, new_boxes, path + moves[d]);
                                                     ~~~~~ ^
3 errors generated.
/in/Compile/Makefile:16: recipe for target 'main' failed
make: *** [main] Error 1