Compilare: user.cpp: In function ‘void Dfs(int, int, int)’: user.cpp:50:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a[n].size(); i++) ^ user.cpp: In function ‘void Write()’: user.cpp:70:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<sol.size(); i++) ^ user.cpp:74:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1; j<sol[i].size(); j++) ^