Compilare: user.cpp: In function ‘long long unsigned int Solve(std::vector<int>&, std::vector<std::pair<std::pair<int, int>, std::vector<int> > >&, int, int, int, int)’: user.cpp:28:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (H.size() != x.first.first) { ^ user.cpp: In function ‘long long int BackForDummies(std::vector<int>&, std::vector<std::pair<std::pair<int, int>, std::vector<int> > >&, int, int, int)’: user.cpp:69:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (H.size() != x.first.first) return 0 ; ^