Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:14:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[x].size();++i) ^ user.cpp:16:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[y].size();++j) ^ user.cpp: In function ‘int main()’: user.cpp:35:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[i].size();++j) ^ user.cpp:36:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0;k<v[i].size();++k) ^ user.cpp:43:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[i].size();++j) ^