Flatten Nested Tree Iterator
Given a nested tree hierarchy (e.g., categories and subcategories), implement an iterator class with a next() method that traverses and returns each node's value in pre-order (top-down, left-to-right) sequence.
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Early June, 2026
Senior
Books ├── Fiction │ ├── Harry Potter │ └── Lord of the Rings └── Science Fiction └── Dune Implement an iterator that traverses the hierarchy and implements next(). next() prints the name of root/category/subcategory. iterator.next() # Books iterator.next() # Fiction iterator.next() # Harry Potter iterator.next() # Lord of the Rings iterator.next() # Science Fiction iterator.next() # Dune
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