<p>Given an <code>m x n</code> binary matrix <code>mat</code>, return <em>the distance of the nearest </em><code>0</code><em> for each cell</em>.</p> <p>The distance between two adjacent cells is <code>1</code>.</p> <p> </p> <p><strong>Example 1:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2021/04/24/01-1-grid.jpg" style="width: 253px; height: 253px;" /> <pre> <strong>Input:</strong> mat = [[0,0,0],[0,1,0],[0,0,0]] <strong>Output:</strong> [[0,0,0],[0,1,0],[0,0,0]] </pre> <p><strong>Example 2:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2021/04/24/01-2-grid.jpg" style="width: 253px; height: 253px;" /> <pre> <strong>Input:</strong> mat = [[0,0,0],[0,1,0],[1,1,1]] <strong>Output:</strong> [[0,0,0],[0,1,0],[1,2,1]] </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 <= 10<sup>4</sup></code></li> <li><code>1 <= m * n <= 10<sup>4</sup></code></li> <li><code>mat[i][j]</code> is either <code>0</code> or <code>1</code>.</li> <li>There is at least one <code>0</code> in <code>mat</code>.</li> </ul>