Sync LeetCode submission Runtime - 2 ms (48.80%), Memory - 39.1 MB (61.72%)

Author: koralkulacoglu

LeetCode/2089-maximum-matrix-sum/README.md

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+<p>You are given an <code>n x n</code> integer <code>matrix</code>. You can do the following operation <strong>any</strong> number of times:</p>
+
+<ul>
+	<li>Choose any two <strong>adjacent</strong> elements of <code>matrix</code> and <strong>multiply</strong> each of them by <code>-1</code>.</li>
+</ul>
+
+<p>Two elements are considered <strong>adjacent</strong> if and only if they share a <strong>border</strong>.</p>
+
+<p>Your goal is to <strong>maximize</strong> the summation of the matrix&#39;s elements. Return <em>the <strong>maximum</strong> sum of the matrix&#39;s elements using the operation mentioned above.</em></p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2021/07/16/pc79-q2ex1.png" style="width: 401px; height: 81px;" />
+<pre>
+<strong>Input:</strong> matrix = [[1,-1],[-1,1]]
+<strong>Output:</strong> 4
+<b>Explanation:</b> 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.
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2021/07/16/pc79-q2ex2.png" style="width: 321px; height: 121px;" />
+<pre>
+<strong>Input:</strong> matrix = [[1,2,3],[-1,-2,-3],[1,2,3]]
+<strong>Output:</strong> 16
+<b>Explanation:</b> We can follow the following step to reach sum equals 16:
+- Multiply the 2 last elements in the second row by -1.
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>n == matrix.length == matrix[i].length</code></li>
+	<li><code>2 &lt;= n &lt;= 250</code></li>
+	<li><code>-10<sup>5</sup> &lt;= matrix[i][j] &lt;= 10<sup>5</sup></code></li>
+</ul>

LeetCode/2089-maximum-matrix-sum/solution.cpp

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+class Solution {
+public:
+    long long maxMatrixSum(vector<vector<int>>& matrix) {
+        int negs = 0;
+        int mn = 1e9;
+        long long sum = 0;
+        for (vector<int>& i : matrix) {
+            for (int j : i) {
+                sum += abs(j);
+                mn = min(mn, abs(j));
+                if (j < 0) negs++;
+            }
+        }
+
+        if (negs % 2 != 0) sum -= 2 * mn;
+        return sum;
+    }
+};