In file included from /in/Compile/check.cpp:7:
/in/sokoban.hpp:97:26: error: implicit conversion changes signedness: 'int' to 'unsigned long' [-Werror,-Wsign-conversion]
            hash =  hash * 31 + box.first * cols + box.second;
                    ~~~~~^~~~ ~
/in/sokoban.hpp:97:37: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
            hash =  hash * 31 + box.first * cols + box.second;
                                ~~~~^~~~~ ~
/in/sokoban.hpp:97:56: error: implicit conversion changes signedness: 'const int' to 'unsigned long' [-Werror,-Wsign-conversion]
            hash =  hash * 31 + box.first * cols + box.second;
                                                 ~ ~~~~^~~~~~
/in/sokoban.hpp:97:50: error: implicit conversion loses integer precision: 'unsigned long' to 'int' [-Werror,-Wshorten-64-to-32]
            hash =  hash * 31 + box.first * cols + box.second;
                 ~  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
4 errors generated.
/in/Compile/Makefile:16: recipe for target 'main' failed
make: *** [main] Error 1