Package g3501_3600.s3531_count_covered_buildings

Class Solution

java.lang.Object

g3501_3600.s3531_count_covered_buildings.Solution

public class Solution
extends Object

3531 - Count Covered Buildings.

Medium

You are given a positive integer n, representing an n x n city. You are also given a 2D grid buildings, where buildings[i] = [x, y] denotes a unique building located at coordinates [x, y].

A building is covered if there is at least one building in all four directions: left, right, above, and below.

Return the number of covered buildings.

Example 1:

Input: n = 3, buildings = [[1,2],[2,2],[3,2],[2,1],[2,3]]

Output: 1

Explanation:

• Only building [2,2] is covered as it has at least one building:
  • above ([1,2])
  • below ([3,2])
  • left ([2,1])
  • right ([2,3])
• Thus, the count of covered buildings is 1.

Example 2:

Input: n = 3, buildings = [[1,1],[1,2],[2,1],[2,2]]

Output: 0

Explanation:

• No building has at least one building in all four directions.

Example 3:

Input: n = 5, buildings = [[1,3],[3,2],[3,3],[3,5],[5,3]]

Output: 1

Explanation:

• Only building [3,3] is covered as it has at least one building:
  • above ([1,3])
  • below ([5,3])
  • left ([3,2])
  • right ([3,5])
• Thus, the count of covered buildings is 1.

Constraints:

• 2 <= n <= 105
• 1 <= buildings.length <= 105
• buildings[i] = [x, y]
• 1 <= x, y <= n
• All coordinates of buildings are unique.

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	countCoveredBuildings(int n, int[][] buildings)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Solution

public Solution()

Method Details

countCoveredBuildings

public int countCoveredBuildings(int n,
 int[][] buildings)