# convex hull for unsorted vertices solved by graham scan algorithm

can graham scan algorithm work with convex hull vertices when vertices are not sorted?

I am investigating a convex hull algorithm that involves sorting. In fact, its running time is limited by sorting, so it is $O(n \log n)$, where $n$ is the number of points on the plane.

That algorithm first sorts the points by x-coordinates. It then includes the first and last points in the convex hull.

• Could you explain or add a link for the "graham scan algorithm" that your question is based on? – András Salamon Oct 17 '15 at 14:49