Algorithm to calculate number of intersecting discs

Question

Given an array A of N integers we draw N discs in a 2D plane, such that i-th disc has center in (0,i) and a radius

Answer 1

Java 2*100%.

result is declared as long for a case codility doesn't test, namely 50k*50k intersections at one point.

class Solution {
    public int solution(int[] A) {

        int[] westEnding = new int[A.length];
        int[] eastEnding = new int[A.length];

        for (int i=0; i=0) eastEnding[i-A[i]]++; else eastEnding[0]++;
            if ((long)i+A[i]10000000) return -1;

            easts--;
            wests-= westEnding[i];
        }

        return (int) result;
    }
}