Resumable 2D Iterator with Pause and Resume Functionality

openai Design a 2D resumable iterator. Implement a class ResumableIterator with the following methods: next(): Returns the next element in the sequence. hasNext(): Returns true if there are more elements to iterate, otherwise returns false. resume(): Resumes iteration from the last stopped point. Requirements: The sequence can be mutable. Operations should be time efficient. Example: # Input: vectors = [[1,2], [3], [4,5,6]] iterator = ResumableIterator(vectors) results = [] while iterator.hasNext(): results.append(iterator.next()) if len(results) == 2: break iterator.resume() # Continue from where it was interrupted # Output: results = [1, 2, 3, 4, 5, 6] Constraints: Each sub-list contains at most 1000 integers. Total integers count 10000. Other parts of the interface should be implemented by yourself. Example Input [[1, 2], [3], [4, 5, 6]]