1. For the following problems, describe a brute-force algorithm for solving them, and determine (an upper bound on the time complexity of your algorithm. = (d) For a given set of points {P1, ... , Pn} = {(t1, y), ..., (Xn, Yn)} in the plane, find the shortest path that starts and ends at P1 = (11,Y) and visits every point at least once. =