Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:11:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<v1[nod].size(); i++) if (!viz[v1[nod][i]]) dfs1(v1[nod][i]); ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:18:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<v2[nod].size(); i++) if (viz[v2[nod][i]]) dfs2(v2[nod][i]); ^ user.cpp: In function ‘int main()’: user.cpp:48:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<sol[i].size(); j++) fout << sol[i][j] << ' '; ^