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g2701_2800.s2768_number_of_black_blocks.readme.md Maven / Gradle / Ivy

2768\. Number of Black Blocks

Medium

You are given two integers `m` and `n` representing the dimensions of a **0-indexed** `m x n` grid.

You are also given a **0-indexed** 2D integer matrix `coordinates`, where `coordinates[i] = [x, y]` indicates that the cell with coordinates `[x, y]` is colored **black**. All cells in the grid that do not appear in `coordinates` are **white**.

A block is defined as a `2 x 2` submatrix of the grid. More formally, a block with cell `[x, y]` as its top-left corner where `0 <= x < m - 1` and `0 <= y < n - 1` contains the coordinates `[x, y]`, `[x + 1, y]`, `[x, y + 1]`, and `[x + 1, y + 1]`.

Return _a **0-indexed** integer array_ `arr` _of size_ `5` _such that_ `arr[i]` _is the number of blocks that contains exactly_ `i` _**black** cells_.

**Example 1:**

**Input:** m = 3, n = 3, coordinates = [[0,0]]

**Output:** [3,1,0,0,0]

**Explanation:** The grid looks like this: ![](https://assets.leetcode.com/uploads/2023/06/18/screen-shot-2023-06-18-at-44656-am.png) 

There is only 1 block with one black cell, and it is the block starting with cell [0,0].

The other 3 blocks start with cells [0,1], [1,0] and [1,1]. They all have zero black cells.

Thus, we return [3,1,0,0,0].

**Example 2:**

**Input:** m = 3, n = 3, coordinates = [[0,0],[1,1],[0,2]]

**Output:** [0,2,2,0,0]

**Explanation:** The grid looks like this: ![](https://assets.leetcode.com/uploads/2023/06/18/screen-shot-2023-06-18-at-45018-am.png) 

There are 2 blocks with two black cells (the ones starting with cell coordinates [0,0] and [0,1]). 

The other 2 blocks have starting cell coordinates of [1,0] and [1,1]. They both have 1 black cell. 

Therefore, we return [0,2,2,0,0].

**Constraints:**

*   2 <= m <= 105
*   2 <= n <= 105
*   0 <= coordinates.length <= 104
*   `coordinates[i].length == 2`
*   `0 <= coordinates[i][0] < m`
*   `0 <= coordinates[i][1] < n`
*   It is guaranteed that `coordinates` contains pairwise distinct coordinates.