クイックハル

Quickhull is a method of computing the convex hull of a finite set of points in n-dimensional space. It uses a divide and conquer approach similar to that of quicksort, from which its name derives. Its worst case time complexity for 2-dimensional and 3-dimensional space is O(n^2), but when the input precision is restricted to O(\log n) bits, its worst case time complexity is conjectured to be O(n \log r), where n is the number of input points and r is the number of processed points (up to n).