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Java-based LeetCode algorithm problem solutions, regularly updated
447\. Number of Boomerangs
Medium
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**.