Minimum Width Color Spanning Annulus

Given a set P of n points in \(I\!\!R^2\), each assigned with one of the k distinct colors, we study the problem of finding the minimum width color spanning annulus of different shapes. Specifically, we consider the circular annulus (CSCA) and axis-parallel square annulus (CSSA). The time and space complexities of the proposed algorithms for both the problems are \(O(n^4\log n)\) and O(n), respectively.