Convex Hull Algorithms

Jarvis march (gift wrapping) finds the convex hull in O(nh) time where h is hull size — optimal for small hulls. Graham scan runs in O(n log n) by first sorting by polar angle. Click to add points, then animate either algorithm.

Controls

Algorithm: Random points: 20 Distribution:

Click canvas to add points, or generate random set.

Jarvis march:
O(nh), h=hull size
Wraps around CCW

Graham scan:
O(n log n)
Sort + stack

Cross product test:
(B-A)×(C-A) > 0
↔ left turn