Smallest Circle Problem
The smallest circle problem for a set of two-dimensional points seeks to find the smallest-radius circle that contains all the points. This Demonstration uses the Matoušek, Sharir and Welzl (MSW) algorithm  that computes the circle for points in expected time. Move the locators to interact with the solution and use the slider to change the number of points.[more]
The built-in Wolfram Language function BoundingRegion uses a similar method.[less]
The smallest circle problem is also known as the minimum covering circle problem, bounding circle problem or smallest enclosing circle problem. For points, a naive solution runs in time, but this randomized algorithm runs in expected linear time, using the MSW algorithm . This recursive algorithm builds and corrects the bounding circle. It returns the minimum circle , with circle center and the radius . See the initialization code for implementations of the functions msw, trivialMinCircle and nonbase.
msw algorithm: input: finite sets and of points in the plane, output: minimal disk enclosing if is empty return trivialMinCircle() choose (randomly and uniformly) if : return
 J. Matsuoka, M. Sharir and E. Welzl, "A Subexponential Bound for Linear Programming," Algorithmica, 16(4–5), 1996 pp. 498–516. doi:10.1007/BF01940877.