<p>Given a <code>m x n</code> matrix <code>mat</code> and an integer <code>threshold</code>, return <em>the maximum side-length of a square with a sum less than or equal to </em><code>threshold</code><em> or return </em><code>0</code><em> if there is no such square</em>.</p> <p> </p> <p><strong>Example 1:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2019/12/05/e1.png" style="width: 335px; height: 186px;" /> <pre> <strong>Input:</strong> mat = [[1,1,3,2,4,3,2],[1,1,3,2,4,3,2],[1,1,3,2,4,3,2]], threshold = 4 <strong>Output:</strong> 2 <strong>Explanation:</strong> The maximum side length of square with sum less than 4 is 2 as shown. </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> mat = [[2,2,2,2,2],[2,2,2,2,2],[2,2,2,2,2],[2,2,2,2,2],[2,2,2,2,2]], threshold = 1 <strong>Output:</strong> 0 </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>m == mat.length</code></li> <li><code>n == mat[i].length</code></li> <li><code>1 <= m, n <= 300</code></li> <li><code>0 <= mat[i][j] <= 10<sup>4</sup></code></li> <li><code>0 <= threshold <= 10<sup>5</sup></code></li> </ul>