Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:16:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod].size();++i) ^ user.cpp:25:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[b].size();++j) ^ user.cpp: In function ‘void solve(int, int)’: user.cpp:41:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod].size();++i) ^