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Java-based LeetCode algorithm problem solutions, regularly updated
1975\. Maximum Matrix Sum
Medium
You are given an `n x n` integer `matrix`. You can do the following operation **any** number of times:
* Choose any two **adjacent** elements of `matrix` and **multiply** each of them by `-1`.
Two elements are considered **adjacent** if and only if they share a **border**.
Your goal is to **maximize** the summation of the matrix's elements. Return _the **maximum** sum of the matrix's elements using the operation mentioned above._
**Example 1:**
![](https://assets.leetcode.com/uploads/2021/07/16/pc79-q2ex1.png)
**Input:** matrix = [[1,-1],[-1,1]]
**Output:** 4
**Explanation:** We can follow the following steps to reach sum equals 4:
- Multiply the 2 elements in the first row by -1.
- Multiply the 2 elements in the first column by -1.
**Example 2:**
![](https://assets.leetcode.com/uploads/2021/07/16/pc79-q2ex2.png)
**Input:** matrix = [[1,2,3],[-1,-2,-3],[1,2,3]]
**Output:** 16
**Explanation:** We can follow the following step to reach sum equals 16: - Multiply the 2 last elements in the second row by -1.
**Constraints:**
* `n == matrix.length == matrix[i].length`
* `2 <= n <= 250`
* -105 <= matrix[i][j] <= 105