Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:15:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i=0;i<a[nod].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:57:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<b[i].size()&&ok;j++) ^ user.cpp:75:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<a[i].size();j++) ^