'''
447. Number of Boomerangs

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]]
'''

import collections


class Solution(object):
    # http://bookshadow.com/weblog/2016/11/06/leetcode-number-of-boomerangs/
    def numberOfBoomerangs(self, points):
        """
        :type points: List[List[int]]
        :rtype: int
        """
        ans = 0
        for x1, y1 in points:
            dmap = collections.defaultdict(int)
            for x2, y2 in points:
                dmap[(x1 - x2) ** 2 + (y1 - y2) ** 2] += 1
            for d in dmap:
                ans += dmap[d] * (dmap[d] - 1)
        return ans

7fcbfc199e5b93010a4efb59e4dacd866e66a9c8
<mask token>

<mask token>


class Solution(object):
    <mask token>

<mask token>


class Solution(object):

    def numberOfBoomerangs(self, points):
        """
        :type points: List[List[int]]
        :rtype: int
        """
        ans = 0
        for x1, y1 in points:
            dmap = collections.defaultdict(int)
            for x2, y2 in points:
                dmap[(x1 - x2) ** 2 + (y1 - y2) ** 2] += 1
            for d in dmap:
                ans += dmap[d] * (dmap[d] - 1)
        return ans

<mask token>
import collections


class Solution(object):

    def numberOfBoomerangs(self, points):
        """
        :type points: List[List[int]]
        :rtype: int
        """
        ans = 0
        for x1, y1 in points:
            dmap = collections.defaultdict(int)
            for x2, y2 in points:
                dmap[(x1 - x2) ** 2 + (y1 - y2) ** 2] += 1
            for d in dmap:
                ans += dmap[d] * (dmap[d] - 1)
        return ans

'''
447. Number of Boomerangs

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]]
'''

import collections


class Solution(object):
    # http://bookshadow.com/weblog/2016/11/06/leetcode-number-of-boomerangs/
    def numberOfBoomerangs(self, points):
        """
        :type points: List[List[int]]
        :rtype: int
        """
        ans = 0
        for x1, y1 in points:
            dmap = collections.defaultdict(int)
            for x2, y2 in points:
                dmap[(x1 - x2) ** 2 + (y1 - y2) ** 2] += 1
            for d in dmap:
                ans += dmap[d] * (dmap[d] - 1)
        return ans
