I received an email from a recruiter one day. They asked some behavioral questions and requested I arrange a pre-screen interview. Two weeks later, we had a phone interview where we used Google Docs for technical questions. The coding question was to generate all combinations of 3-digit numbers with no duplicate digits. Zero could be at the first digit. However, I think I was too nervous to respond to the question well.

First, a mathematical question, asking about the number of possible combinations in a card game based on the given rules.

Second, let you print out all combinations of 3-digit numbers with no duplicates, e.g., 012, 013, ... 123, 124, 125...