I was contacted by a recruiter and applied for that position online. Then, we scheduled a phone screen for the following week.

In the phone interview, we quickly went over my resume and soon jumped to the skill-testing part to solve an algorithm problem. The problem was somewhat vague. I was asked for a declaration and received an easy 'Yes' or 'No' as feedback.

Not a very ideal interview experience.

You have an in-memory tree data structure. Each node can have multiple children (more than two). It is not a search or balanced tree.

Task: Serialize it to a file so that you can deserialize it later with the same structure. Node values can be any integers.