Your question is Permutations, Graph Traversal, and Tick-Tak-Toe. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Tech screening was a task to generate all possible permutations given a set of rules. Main coding challenge: graph traversal problem (DFS or BFS is enough). System design: Design an online game of a Tick-Tak-Toe.