Smallest Hitting Set: Design and analyze an efficient greedy algorithm for the following problem:
Input: A set P = { p1, p2, ... , pn} of points, and a set I = { I1, I2, ... , Im} of intervals, all on the real line. These intervals and points are given in no particular order. Each interval is given by its starting and finishing times.
Output: (i) A minimum cardinality subset H of P such that every interval in I is hit by (i.e., contains) at least one point in H, or
(ii) an interval Ik ? I that is not hit by any point in P.