Remove type cast in combinations algorithm (#7607)

* Remove commented-out print statements in algorithmic functions

* Encapsulate non-algorithmic code in __main__

* Remove unused print_matrix function

* Remove print statement in __init__

* Remove print statement from doctest

* Encapsulate non-algorithmic code in __main__

* Modify algorithm to return instead of print

* Encapsulate non-algorithmic code in __main__

* Refactor data_safety_checker to return instead of print

* updating DIRECTORY.md

* updating DIRECTORY.md

* Apply suggestions from code review

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* updating DIRECTORY.md

* Remove int cast and change float division to int division

* Move new-line chars

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>