Compilare: main.cpp: In function 'bool try_path(int)': main.cpp:82:10: warning: converting to 'std::queue<Pos>' from initializer list would use explicit constructor 'std::queue<_Tp, _Sequence>::queue(_Sequence&&) [with _Tp = Pos; _Sequence = std::deque<Pos, std::allocator<Pos> >]' q = {}; ^ main.cpp:82:10: note: in C++11 and above a default constructor can be explicit