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]]

class Solution(object):

    def numberOfBoomerangs(self, points):

        """

        :type points: List[List[int]]

        :rtype: int

        """

        ans=0

        for i in points:

            a={}

            for j in points:

                c=(i[0]-j[0])**2+(i[1]-j[1])**2

                if c not in a:

                    a[c]=1

                else:

                    ans+=a[c]

                    a[c]+=1

        return ans*2