In file included from /in/Compile/check.cpp:7:
/in/sokoban.hpp:96:47: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
            size_t new_r = player.first + dir.first;
                                        ~ ~~~~^~~~~
/in/sokoban.hpp:97:48: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
            size_t new_c = player.second + dir.second;
                                         ~ ~~~~^~~~~~
/in/sokoban.hpp:106:44: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
                size_t box_r = new_r + dir.first;
                                     ~ ~~~~^~~~~
/in/sokoban.hpp:107:44: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
                size_t box_c = new_c + dir.second;
                                     ~ ~~~~^~~~~~
4 errors generated.
/in/Compile/Makefile:16: recipe for target 'main' failed
make: *** [main] Error 1