Compilare: user.cpp: In function ‘void getHull(std::vector<Line>&)’: user.cpp:75:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < lines.size(); ++ i) { ^ user.cpp: In function ‘int main()’: user.cpp:162:29: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (B < 0 || B == 0 && A < 0) { ^