Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:19:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a[x].size();i++) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:27:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<b[x].size();j++) ^ user.cpp: In function ‘int main()’: user.cpp:49:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v.size();j++) ^ user.cpp:60:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<ans[i].size();j++) ^