Compilare: user.cpp: In function ‘int main()’: user.cpp:50:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<V[v].size();++i) ^ user.cpp:71:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1;i<Sol.size();++i) cout<<Sol[i].first<<" "<<Sol[i].second<<"\n"; ^ user.cpp:32:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin); ^ user.cpp:33:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out","w",stdout); ^