Flatten Nested List Iterator

Problem

Simulate an iterator that flattens a nested list lazily.

nested is a list whose elements are integers or nested lists; operations contains "next" and "has_next". next returns the next integer in flattened order and has_next reports whether more remain. The iterator is consumed in order.

Return the list of recorded results.

Hint

You may flatten eagerly into a list and then serve it with a position pointer.

Test cases

case 1

in: [[1,[2,3],4],["has_next","next","next","has_next","next","next","has_next"]]

expected: [true,1,2,true,3,4,false]

case 2

in: [[],["has_next"]]

expected: [false]

case 3

in: [[[[1]]],["next","has_next"]]

expected: [1,false]

case 4

in: [[[1,2]],["next","next"]]

expected: [1,2]

Starter codePython

def nested_iterator_ops(nested, operations):
    # Your code here
    pass

4 test cases · run your code against them in the editor