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"content": "<p>A <code>3 x 3</code> magic square is a <code>3 x 3</code> grid filled with distinct numbers <strong>from </strong><code>1</code><strong> to </strong><code>9</code> such that each row, column, and both diagonals all have the same sum.</p>\n\n<p>Given a <code>row x col</code> <code>grid</code> of integers, how many <code>3 x 3</code> "magic square" subgrids are there? (Each subgrid is contiguous).</p>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/09/11/magic_main.jpg\" style=\"width: 322px; height: 242px;\" />\n<pre>\n<strong>Input:</strong> grid = [[4,3,8,4],[9,5,1,9],[2,7,6,2]]\n<strong>Output:</strong> 1\n<strong>Explanation: </strong>\nThe following subgrid is a 3 x 3 magic square:\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/09/11/magic_valid.jpg\" style=\"width: 242px; height: 242px;\" />\nwhile this one is not:\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/09/11/magic_invalid.jpg\" style=\"width: 242px; height: 242px;\" />\nIn total, there is only one magic square inside the given grid.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> grid = [[8]]\n<strong>Output:</strong> 0\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>row == grid.length</code></li>\n\t<li><code>col == grid[i].length</code></li>\n\t<li><code>1 <= row, col <= 10</code></li>\n\t<li><code>0 <= grid[i][j] <= 15</code></li>\n</ul>\n",
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