Compilare: main.cpp: In function 'void MakeSet(std::vector<std::pair<int, int> >&)': main.cpp:25:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < x.size(); i++) ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:56:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); i++) ~~^~~~~~~~~~