* Type annotations for `breadth_first_search.py`
* Type annotations for `breadth_first_search_2.py`
* Remove from excluded in mypy.ini
* Add doctest.testmod()
* Type annotations for `graphs/check_cycle.py`
* Type annotations for `graphs/greedy_min_vertex_cover.py`
* Remove from excluded in mypy.ini
* Update queue implementation
Popping the first element of a list takes O(n) time.
Using a cyclic queue takes O(1) time.
* Add queue changes from extra files
* Update indentation
* Add empty line between imports
* Fix lines
* Apply suggestions from code review
Co-authored-by: John Law <johnlaw.po@gmail.com>
Co-authored-by: John Law <johnlaw.po@gmail.com>