Part of course:
Quick-Hull: A quick-sort like algorithm for convex hull
The algorithm has a worst case run-time of O(n^2) and an average case run-time of O(n log n). However, note that it is possible for people to design data for which this algorithm will take O(n^2) time. For example, the algorithm has a bad run time when the points are located on the circumference of a circle.