Compilare: main.cpp: In member function 'void convex_hull::calculate()': main.cpp:32:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();i++) ~^~~~~~~~~ main.cpp:37:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();i++) ~^~~~~~~~~ main.cpp: In member function 'int convex_hull::get_mn()': main.cpp:54:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ret+(1<<p)+1<st.size()&&det(st[ret+(1<<p)],A,B)>=det(st[ret+(1<<p)+1],A,B)) ~~~~~~~~~~~~^~~~~~~~~~ main.cpp:57:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ret+1<st.size()&&det(st[ret+1],A,B)<0) return 1; ~~~~~^~~~~~~~~~ main.cpp: In function 'void build(int, int, int)': main.cpp:72:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ch[2*nod].st.size();i++) ~^~~~~~~~~~~~~~~~~~~~ main.cpp:74:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ch[2*nod+1].st.size();i++) ~^~~~~~~~~~~~~~~~~~~~~~