In file included from /in/Compile/check.cpp:7:
/in/sokoban.hpp:264:36: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
                size_t new_r = r + dir[0];
                                 ~ ^~~~~~
/in/sokoban.hpp:265:36: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
                size_t new_c = c + dir[1];
                                 ~ ^~~~~~
2 errors generated.
/in/Compile/Makefile:16: recipe for target 'main' failed
make: *** [main] Error 1