Compilare: main.cpp: In function 'int main()': main.cpp:140:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < events.size(); i++) ~~^~~~~~~~~~~~~~~ main.cpp:142:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i + 1 < events.size() && events[i].first == events[i + 1].first) ~~~~~~^~~~~~~~~~~~~~~