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37 lines
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37 lines
1.5 KiB
HTML
<p>A <code>3 x 3</code> <strong>magic square</strong> is a <code>3 x 3</code> grid filled with distinct numbers <strong>from </strong>1<strong> to </strong>9 such that each row, column, and both diagonals all have the same sum.</p>
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<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?</p>
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<p>Note: while a magic square can only contain numbers from 1 to 9, <code>grid</code> may contain numbers up to 15.</p>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2020/09/11/magic_main.jpg" style="width: 322px; height: 242px;" />
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<pre>
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<strong>Input:</strong> grid = [[4,3,8,4],[9,5,1,9],[2,7,6,2]]
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<strong>Output:</strong> 1
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<strong>Explanation: </strong>
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The following subgrid is a 3 x 3 magic square:
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<img alt="" src="https://assets.leetcode.com/uploads/2020/09/11/magic_valid.jpg" style="width: 242px; height: 242px;" />
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while this one is not:
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<img alt="" src="https://assets.leetcode.com/uploads/2020/09/11/magic_invalid.jpg" style="width: 242px; height: 242px;" />
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In total, there is only one magic square inside the given grid.
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</pre>
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<p><strong class="example">Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> grid = [[8]]
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<strong>Output:</strong> 0
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>row == grid.length</code></li>
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<li><code>col == grid[i].length</code></li>
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<li><code>1 <= row, col <= 10</code></li>
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<li><code>0 <= grid[i][j] <= 15</code></li>
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</ul>
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