Compilare: main.cpp: In function 'std::vector<std::pair<int, int> > intersect(std::vector<std::pair<int, int> >&, std::vector<std::pair<int, int> >&)': main.cpp:16:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<prev.size(); ++i) ~^~~~~~~~~~~~ main.cpp:17:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<ref.size(); ++j) ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:82:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int c = 0; c<interv[j].size(); ++c) ~^~~~~~~~~~~~~~~~~