# 0598. Range Addition II

<https://leetcode.com/problems/range-addition-ii>

## Description

You are given an `m x n` matrix `M` initialized with all `0`'s and an array of operations `ops`, where `ops[i] = [ai, bi]` means `M[x][y]` should be incremented by one for all `0 <= x < ai` and `0 <= y < bi`.

Count and return *the number of maximum integers in the matrix after performing all the operations*.

**Example 1:**

![](https://assets.leetcode.com/uploads/2020/10/02/ex1.jpg)

```
**Input:** m = 3, n = 3, ops = [[2,2],[3,3]]
**Output:** 4
**Explanation:** The maximum integer in M is 2, and there are four of it in M. So return 4.
```

**Example 2:**

```
**Input:** m = 3, n = 3, ops = [[2,2],[3,3],[3,3],[3,3],[2,2],[3,3],[3,3],[3,3],[2,2],[3,3],[3,3],[3,3]]
**Output:** 4
```

**Example 3:**

```
**Input:** m = 3, n = 3, ops = []
**Output:** 9
```

**Constraints:**

* `1 <= m, n <= 4 * 104`
* `0 <= ops.length <= 104`
* `ops[i].length == 2`
* `1 <= ai <= m`
* `1 <= bi <= n`

## ac

```java
```