You are given a stream of points on the X-Y plane. Design an algorithm that:
1. Adds new points from the stream into a data structure. Duplicate points are allowed and should be treated as different points.
2. Given a query point, counts the number of ways to choose three points from the data structure such that the three points and the query point form an axis-aligned square with positive area.
An axis-aligned square is a square whose edges are all aligned with the x-axis and y-axis.
Implement the DetectSquares class:
- DetectSquares() Initializes the object with an empty data structure.
- void add(int[] point) Adds a new point point = [x, y] to the data structure.
- int count(int[] point) Counts the number of ways to form axis-aligned squares with point point = [x, y] as one of the vertices of the squares.
Constraints:
point.length == 2
0 <= x, y <= 1000
At most 3000 calls in total will be made to add and count.