In file included from /in/Compile/check.cpp:7:
/in/sokoban.hpp:29:36: error: implicit conversion changes signedness: 'int' to 'unsigned long' [-Werror,-Wsign-conversion]
    size_t x = static_cast<size_t>(pos / cols);
                                   ^~~ ~
/in/sokoban.hpp:30:36: error: implicit conversion changes signedness: 'int' to 'unsigned long' [-Werror,-Wsign-conversion]
    size_t y = static_cast<size_t>(pos % cols);
                                   ^~~ ~
/in/sokoban.hpp:137:36: error: use of undeclared identifier 'answers'
    if (index < 1 || index >= (int)answers.size()) {
                                   ^
/in/sokoban.hpp:140:12: error: use of undeclared identifier 'answers'
    return answers[(size_t)index];
           ^
4 errors generated.
/in/Compile/Makefile:16: recipe for target 'main' failed
make: *** [main] Error 1