[LeetCode] Problem 447 - Number of Boomerangs

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Given n points in the plane that are all pairwise distinct, a “boomerang” is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k (the order of the tuple matters).

Find the number of boomerangs. You may assume that n will be at most 500 and coordinates of points are all in the range [-10000, 10000] (inclusive).

Example

Input:
[[0,0],[1,0],[2,0]]

Output:
2

Explanation:
The two boomerangs are [[1,0],[0,0],[2,0]] and [[1,0],[2,0],[0,0]]

Code

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public int numberOfBoomerangs(int[][] points) {
    int result = 0;
    Map<Integer, Integer> map = new HashMap<>();

    for (int i = 0; i < points.length; i++) {
        for (int j = 0; j < points.length; j++) {                
            int distance = getDistance(points[i], points[j]);
            map.put(distance, map.getOrDefault(distance, 0) + 1);
        }

        for (Map.Entry<Integer, Integer> entry : map.entrySet())
            result += entry.getValue() * (entry.getValue() - 1);

        map.clear();
    }

    return result;
}

private int getDistance(int[] a, int[] b) {
    int x = a[0] - b[0];
    int y = a[1] - b[1];
    return x * x + y * y;
}