Compilare: user.cpp: In function ‘int main()’: user.cpp:60:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<V.size();i++) ^ user.cpp:61:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<O.size();j++) ^ user.cpp:63:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<O.size();i++) ^ user.cpp:64:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=i+1;j<O.size();j++) ^ user.cpp:67:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k=0;k<V.size();k++) ^