This is an interview question: How to serialize a graph ? I saw this answer but I am not sure if this is enough.

It looks like a very confusing "open question" and the candidates are probably expected to ask more questions about the requirements: what the nodes and edges are, how they are serialized themselves, is this graph weighted, directed, etc., how many nodes/edges are in the graph.What about the infrastructure ? Is it a plain file system or we should/can use a database ?

So, how would you answer this question ?