Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:31:31: 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:132:12: warning: ‘cost’ may be used uninitialized in this function [-Wmaybe-uninitialized] out << cost << " " << n1 << " " << n2 << "\n"; ^ user.cpp:132:40: warning: ‘n2’ may be used uninitialized in this function [-Wmaybe-uninitialized] out << cost << " " << n1 << " " << n2 << "\n"; ^ user.cpp:132:27: warning: ‘n1’ may be used uninitialized in this function [-Wmaybe-uninitialized] out << cost << " " << n1 << " " << n2 << "\n"; ^