Remember the problem with the phone base stations. Here we will see a variation of this problem. This time there are houses scattered sparsely along the perimeter of a circular lake with radius far longer than 4 miles. The positions of the houses are given to you. Your goal is to place as few phone base stations as possible, along the perimeter, ensuring that every house is within 4 miles from some base station (you can assume that every phone base station is covering an arc of 8 miles with its position as the middle point of the arc). Give an algorithm with time complexity O(n 2 ).