I once had a Hackerrank problem that ultimately boiled down to "merge these sorted lists." I had 15 minutes, I think, to code the solution. I spent 10 of them deciding whether to use list.sort(), then finally just did it and cited the paper linked in On the Worst-Case Complexity of TimSort to claim linear time.
Timsort, the Python sorting algorithm - https://news.ycombinator.com/item?id=21196555 - Oct 2019 (131 comments)
On the Worst-Case Complexity of TimSort - https://news.ycombinator.com/item?id=17883461 - Aug 2018 (74 comments)
Timsort is a sorting algorithm that is efficient for real-world data - https://news.ycombinator.com/item?id=17436591 - July 2018 (77 comments)
Functional verification with mechanical proofs of TimSort [pdf] - https://news.ycombinator.com/item?id=9778243 - June 2015 (1 comment)
Timsort - https://news.ycombinator.com/item?id=3214527 - Nov 2011 (27 comments)
Java has switched from Mergesort to TimSort - https://news.ycombinator.com/item?id=752677 - Aug 2009 (13 comments)