Compilare: user.cpp: In function ‘bool bfs()’: user.cpp:21:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[start].size();i++) ^ user.cpp: In function ‘void support(int)’: user.cpp:36:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[x].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:55:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<s.size();j++) ^