def convex_hull_nlogn(pts):
left_most = min(pts)
#sort - O(nlog(n))
sorted_pts = sorted(pts, cmp=functools.partial(compare, origin=left_most))
hull = [left_most, sorted_pts.pop(0), sorted_pts.pop(0)]
for pt in sorted_pts:#O(n)
while find_left_right(Ln(hull[-1], hull[-2]), pt) < 0: #left turn
hull.pop()
hull.append(pt)
return hull
def intersect(l1, l2):
dir1, dir2 = find_left_right(l1, l2.pt1), find_left_right(l1, l2.pt2)
return not ((dir1 > 0 and dir2 > 0) or (dir1 < 0 and dir2 < 0) or (dir1 == dir2 == 0))
def intersect(l1, l2):
dir1, dir2 = find_left_right(l1, l2.pt1), find_left_right(l1, l2.pt2)
return not ((dir1 > 0 and dir2 > 0) or (dir1 < 0 and dir2 < 0) or
(dir1 == dir2 == 0))