In a 2-D plane, a point P(x,y) is said to be dominated by some point Q(h, k), if (x <= h) and (y <= k). Given n 2-D points there can be points not-dominated by any other point. Wiki-link here can be help with the definition. Also the definition is true for higher dimensions as well.
We find all non-dominated points and label them as Layer 1. And then remove them, we label each layer increasingly unless all the points are labeled.
Can this (labeling all points with there correct layers) be done in O(n log n) time?