- java.lang.Object
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- g2001_2100.s2013_detect_squares.DetectSquares
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public class DetectSquares extends Object
2013 - Detect Squares.
Medium
You are given a stream of points on the X-Y plane. Design an algorithm that:
- Adds new points from the stream into a data structure. Duplicate points are allowed and should be treated as different points.
- 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 the same length and are either parallel or perpendicular to the x-axis and y-axis.
Implement the
DetectSquaresclass:DetectSquares()Initializes the object with an empty data structure.void add(int[] point)Adds a new pointpoint = [x, y]to the data structure.int count(int[] point)Counts the number of ways to form axis-aligned squares with pointpoint = [x, y]as described above.
Example 1:
Input [“DetectSquares”, “add”, “add”, “add”, “count”, “count”, “add”, “count”] [ [], 10, 2, 2, 10, 8, 2, 10]
Output: [null, null, null, null, 1, 0, null, 2]
Explanation:
DetectSquares detectSquares = new DetectSquares();
detectSquares.add([3, 10]);
detectSquares.add([11, 2]);
detectSquares.add([3, 2]);
detectSquares.count([11, 10]); // return 1. You can choose: // - The first, second, and third points
detectSquares.count([14, 8]); // return 0. The query point cannot form a square with any points in the data structure.
detectSquares.add([11, 2]); // Adding duplicate points is allowed.
detectSquares.count([11, 10]); // return 2. You can choose: // - The first, second, and third points // - The first, third, and fourth points
Constraints:
point.length == 20 <= x, y <= 1000- At most
3000calls in total will be made toaddandcount.
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Constructor Summary
Constructors Constructor and Description DetectSquares()
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