19. Given n points on a line, the n points are the n users who need wifi signal. Suppose that we have only one kind of wifi router and we don't care about the number of wifi routers needed, but we have to minimize the power consumption of the routers. Power consumption is presented as the distance that signal of a router can reach.

(a) Design a Divide and Conquer algorithm to determine the minimum power consumption. (4%).

(b) What is the time required for your Divide and Conquer algorithm? (2%).