447. Number of Boomerangs

/*
Time Complexity: O(N^2)
Space Complexity :O(N)

N = Number of points.
*/
class Solution {
    public int numberOfBoomerangs(int[][] points) {
        if (points == null || points.length < 3 || points[0].length != 2) {
            return 0;
        }

        HashMap<Integer, Integer> map = new HashMap();
        int result = 0;

        for (int i = 0; i < points.length; i++) {
            for (int j = 0; j < points.length; j++) {
                if (i == j) {
                    continue;
                }

                int dist = getDistance(points[i], points[j]);
                map.put(dist, map.getOrDefault(dist, 0) + 1);
            }

            for (int val : map.values()) {
                result += val * (val - 1);
            }

            map.clear();
        }

        return result;
    }

    private int getDistance(int[] A, int[] B) {
        int dx = A[0] - B[0];
        int dy = A[1] - B[1];

        return dx*dx + dy*dy;
    }
}