0447. Number of Boomerangs

https://leetcode.com/problems/number-of-boomerangs

Description

You are given n points in the plane that are all distinct, where points[i] = [xi, yi]. 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).

Return the number of boomerangs.

Example 1:

**Input:** points = [[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]].

Example 2:

**Input:** points = [[1,1],[2,2],[3,3]]
**Output:** 2

Example 3:

**Input:** points = [[1,1]]
**Output:** 0

Constraints:

• n == points.length

• 1 <= n <= 500

• points[i].length == 2

• -104 <= xi, yi <= 104

• All the points are unique.

ac