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.
Examples
Example 1
Input: n = 3, buildings = [[1,2],[2,2],[3,2],[2,1],[2,3]]
Output: 1
Explanation:
Example 2
Input: n = 3, buildings = [[1,1],[1,2],[2,1],[2,2]]
Output: 0
Explanation:
Example 3
Input: n = 5, buildings = [[1,3],[3,2],[3,3],[3,5],[5,3]]
Output: 1
Explanation:
Constraints
2 <= n <= 105
1 <= buildings.length <= 105
buildings[i] = [x, y]
1 <= x, y <= n
All coordinates of buildings are unique.
3531. Count Covered Buildings
Medium
30 Points
Array
Hash Table
Sorting
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.
Examples
Example 1
Input: n = 3, buildings = [[1,2],[2,2],[3,2],[2,1],[2,3]]
Output: 1
Explanation:
Example 2
Input: n = 3, buildings = [[1,1],[1,2],[2,1],[2,2]]
Output: 0
Explanation:
Example 3
Input: n = 5, buildings = [[1,3],[3,2],[3,3],[3,5],[5,3]]
Output: 1
Explanation:
Constraints
2 <= n <= 105
1 <= buildings.length <= 105
buildings[i] = [x, y]
1 <= x, y <= n
All coordinates of buildings are unique.
Count Covered Buildings - Practice Coding | SlaveCode