"""
Solution to the ADT puzzle from lecture; no ADTS.
This is slow!
"""

from typing import List


def puzzle(lst: List[int]) -> List[int]:
    """Solve the puzzle."""
    i = 0
    while i < len(lst) - 1:
        if lst[i] + 1 == lst[i + 1]:
            lst[i] = 2 * lst[i] + 1
            lst.pop(i + 1)
            i = 0
        else:
            i = i + 1
    return lst


if __name__ == '__main__':
    import time
    items = list(range(10000))

    # start the clock
    start = time.time()

    puzzle(items)

    end = time.time()
    print(f"It took {end - start} seconds without using any ADTs")