The tricky part is that the problem doesn't tell you how many children each node gets, you have to decide.
First, clarify the tree construction rules: how digits map to nodes and parent-child relationships. Then, choose an efficient representation (e.g., adjacency list) and build the tree, followed by a standard BFS for level-order traversal. Discuss time and space complexity.
Pro tip: Mention edge cases like empty input or single node, and ask if the tree should be built level by level or based on digit values. This shows attention to detail and proactive clarification.
Ask questions to understand how the tree is constructed from the digits. For example, is it a complete N-ary tree where each node can have up to N children, or is the structure defined by the digits themselves?
Decide on a node representation (e.g., class with value and children list) and a way to build the tree (e.g., using a queue for level-by-level construction).
Iterate through the digits and construct the tree according to the clarified rules. Handle edge cases like empty input.
Use a queue to traverse the tree level by level, collecting node values in order. Ensure each level is processed separately if needed.
State the time and space complexity: O(n) time and O(n) space for both building and traversal, where n is the number of digits.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.