hyunsik-yoon
commented
1 year ago From many sources,
- https://www.geeksforgeeks.org/sort-algorithms-the-c-standard-template-library-stl/
- https://www.techiedelight.com/introsort-algorithm/
IntroSort is used, which is mixture of quick sort and heap sort.
When the number of elements are small, insertion sort is used.
This was asked by chapter 190. Let's find out.