c5

First, regarding the line intersection: you do not need the actual point of intersection, only to know if they intersect. See http://www.geeksforgeeks.org/check-if-two-given-line-segments-intersect/ for an algorithm that does just that. About the List implementation: In your implementation using Lists, you call indexOf on the sweepline to find nl. This searches the sweepline from start to end. … Read more