Compilare: user.cpp: In function ‘void dfs(int, int&, int)’: user.cpp:44:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘void solve2()’: user.cpp:72:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); ++i) ^