(Abridged notes from Introduction to Algorithms)
Branch of CS that studies algorithms for solving geometric problems. Input is typically a set of points, a set of line segments, or the vertices of a polygon in counterclockwise order. Output is often a response to a query about the objects, such as whether any lines intersect, or finding a new geometric object (e.g. convex hull) of the set of points.
We look at computational-geometry algorithms in two dimensions (2D), i.e. in the plane.
Each object is represented by a set of points {P1, P2, P3, ...}, where each Pi = (Xi, Yi).
For example, an n-vertex polygon _P = _.