Efficiency

The algorithm as described above has complexity of O(N²), N being the number of polygons in the input. The efficiency greatly depends on the efficiency of the clipping algorithm which itself has complexity of O(M N) as described previously. But since a significant number of polygons in a typical input are disjoint (i.e. not all polygons in the list necessarily intersect each other), the polygon clipping routine on an average has a complexity of much less than O(N²) for sufficiently large N. Thus, the typical time complexity of the algorithm would be O(N³).