Compilare: user.cpp: In function ‘void check(long long int&, std::vector<int>&, std::vector<int>&, std::vector<std::pair<int, int> >&, std::vector<int>&)’: user.cpp:65:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sol.size(); j ++) { ^ user.cpp:69:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = j; k < sol.size(); k ++) { ^