<p>Given an <code>m x n</code> <code>matrix</code>, return <em><code>true</code> if the matrix is Toeplitz. Otherwise, return <code>false</code>.</em></p> <p>A matrix is <strong>Toeplitz</strong> if every diagonal from top-left to bottom-right has the same elements.</p> <p> </p> <p><strong>Example 1:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2020/11/04/ex1.jpg" style="width: 322px; height: 242px;" /> <pre> <strong>Input:</strong> matrix = [[1,2,3,4],[5,1,2,3],[9,5,1,2]] <strong>Output:</strong> true <strong>Explanation:</strong> In the above grid, the diagonals are: "[9]", "[5, 5]", "[1, 1, 1]", "[2, 2, 2]", "[3, 3]", "[4]". In each diagonal all elements are the same, so the answer is True. </pre> <p><strong>Example 2:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2020/11/04/ex2.jpg" style="width: 162px; height: 162px;" /> <pre> <strong>Input:</strong> matrix = [[1,2],[2,2]] <strong>Output:</strong> false <strong>Explanation:</strong> The diagonal "[1, 2]" has different elements. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>m == matrix.length</code></li> <li><code>n == matrix[i].length</code></li> <li><code>1 <= m, n <= 20</code></li> <li><code>0 <= matrix[i][j] <= 99</code></li> </ul> <p> </p> <p><strong>Follow up:</strong></p> <ul> <li>What if the <code>matrix</code> is stored on disk, and the memory is limited such that you can only load at most one row of the matrix into the memory at once?</li> <li>What if the <code>matrix</code> is so large that you can only load up a partial row into the memory at once?</li> </ul>