# 1351. Count Negative Numbers in a Sorted Matrix

https://leetcode.com/problems/count-negative-numbers-in-a-sorted-matrix

## Description

Given a `m x n` matrix `grid` which is sorted in non-increasing order both row-wise and column-wise, return _the number of **negative** numbers in_ `grid`.

**Example 1:**

```
**Input:** grid = [[4,3,2,-1],[3,2,1,-1],[1,1,-1,-2],[-1,-1,-2,-3]]
**Output:** 8
**Explanation:** There are 8 negatives number in the matrix.
```

**Example 2:**

```
**Input:** grid = [[3,2],[1,0]]
**Output:** 0
```

**Example 3:**

```
**Input:** grid = [[1,-1],[-1,-1]]
**Output:** 3
```

**Example 4:**

```
**Input:** grid = [[-1]]
**Output:** 1
```

**Constraints:**

* `m == grid.length`
* `n == grid[i].length`
* `1 <= m, n <= 100`
* `-100 <= grid[i][j] <= 100`

**Follow up:** Could you find an `O(n + m)` solution?

## ac

```java
```
