447. Number of Boomerangs

Medium

30 Points

Array

Hash Table

Math

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.

Examples

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.