Compilare: user.cpp: In function ‘poligon intersect(poligon, point, point)’: user.cpp:57:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<P.size()-1; ++i) ~^~~~~~~~~~~ user.cpp: In function ‘ll solve(poligon, poligon)’: user.cpp:73:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; !a.empty() && i<b.size()-1; ++i) ~^~~~~~~~~~~ user.cpp:89:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<a.size()-1; ++i) ~^~~~~~~~~~~