# 0533. Lonely Pixel II

<https://leetcode.com/problems/lonely-pixel-ii>

## Description

Given an `m x n` `picture` consisting of black `'B'` and white `'W'` pixels and an integer target, return *the number of **black** lonely pixels*.

A black lonely pixel is a character `'B'` that located at a specific position `(r, c)` where:

* Row `r` and column `c` both contain exactly `target` black pixels.
* For all rows that have a black pixel at column `c`, they should be exactly the same as row `r`.

**Example 1:**

![](https://assets.leetcode.com/uploads/2021/04/24/pixel2-1-grid.jpg)

```
**Input:** picture = [["W","B","W","B","B","W"],["W","B","W","B","B","W"],["W","B","W","B","B","W"],["W","W","B","W","B","W"]], target = 3
**Output:** 6
**Explanation:** All the green 'B' are the black pixels we need (all 'B's at column 1 and 3).
Take 'B' at row r = 0 and column c = 1 as an example:
 - Rule 1, row r = 0 and column c = 1 both have exactly target = 3 black pixels. 
 - Rule 2, the rows have black pixel at column c = 1 are row 0, row 1 and row 2. They are exactly the same as row r = 0.
```

**Example 2:**

![](https://assets.leetcode.com/uploads/2021/04/24/pixel2-2-grid.jpg)

```
**Input:** picture = [["W","W","B"],["W","W","B"],["W","W","B"]], target = 1
**Output:** 0
```

**Constraints:**

* `m == picture.length`
* `n == picture[i].length`
* `1 <= m, n <= 200`
* `picture[i][j]` is `'W'` or `'B'`.
* `1 <= target <= min(m, n)`

## ac

```java
```


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