Compilare: user.cpp: In function ‘std::vector<std::pair<long long int, long long int> > convexa(std::vector<std::pair<long long int, long long int> >, int)’: user.cpp:17:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<p.size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:34:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0,j=0;i+1<ls.size();++i) ^ user.cpp:35:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] { for(;det(ls[i],ls[i+1],lj[j]) && j<lj.size();++j); ^ user.cpp:36:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j==lj.size()) {p1=ls[i]; break;} ^ user.cpp:38:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i+1<lj.size();++i) ^