Compilare: user.cpp: In function ‘int query(int)’: user.cpp:69:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ant+i<env.size() && t>env[ant+i].x) ^ user.cpp: In function ‘int main()’: user.cpp:87:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ls.size(); ++i) { /// Select 'lower envelope' lines ^ user.cpp:95:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<stk.size(); ++i) /// Make 'lower envelope' ^