Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:12:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:36:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<W.size();++i) ^ user.cpp:37:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0,x=W[i].second;j<G[x].size();++j) ^ user.cpp:51:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<Q.size();++i) viz[Q[i].second]=1; ^ user.cpp:52:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<Q.size();++i) ^