963. Minimum Area Rectangle II

class Solution {
    public double minAreaFreeRect(int[][] points) {
        Map<Integer, Set<Integer>> map = new HashMap<>();
        for (int[] point : points) {
            int x = point[0], y = point[1];
            if (!map.containsKey(x)) {
                map.put(x, new HashSet<>());
            }

            map.get(x).add(y);
        }

        double min = Double.MAX_VALUE;
        int n = points.length;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                int dx1 = points[j][0] - points[i][0];
                int dy1 = points[j][1] - points[i][1];

                for (int k = j + 1; k < n; k++) {
                    int dx2 = points[k][0] - points[i][0];
                    int dy2 = points[k][1] - points[i][1];

                    if (dx1 * dx2 + dy1 * dy2 != 0) continue;

                    int x = dx1 + points[k][0];
                    int y = dy1 + points[k][1];

                    if (map.get(x) != null && map.get(x).contains(y)) {
                double area = Math.sqrt(dx1 * dx1 + dy1 * dy1) *
                Math.sqrt(dx2 * dx2 + dy2 * dy2);

                        if (area < min) {
                            min = area;
                        }
                    }
                }
            }
        }

        return min == Double.MAX_VALUE ? 0 : min;
    }
}