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**Graham's Scan Algorithm** is an efficient algorithm for finding the convex hull of a finite set of points in the plane with time complexity O(N log N). The algorithm finds all vertices of the convex hull ordered along its boundary. **It uses a stack to detect and remove concavities in the boundary efficiently**.

This is a companion discussion topic for the original entry at http://iq.opengenus.org/graham-scan-convex-hull/