Number of Disc Intersection
Problem We draw N discs on a plane. The discs are numbered from 0 to N − 1. An array A of N non-negative integers, specifying the radiuses of the discs, is given. The J-th disc is drawn with its center at (J, 0) and radius AJ. We say that the J-th disc and K-th disc intersect if J ≠ K and the J-th…