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42 lines
1.4 KiB
HTML
42 lines
1.4 KiB
HTML
<p>Given a square matrix <code>mat</code>, return the sum of the matrix diagonals.</p>
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<p>Only include the sum of all the elements on the primary diagonal and all the elements on the secondary diagonal that are not part of the primary diagonal.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2020/08/14/sample_1911.png" style="width: 336px; height: 174px;" />
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<pre>
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<strong>Input:</strong> mat = [[<strong>1</strong>,2,<strong>3</strong>],
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[4,<strong>5</strong>,6],
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[<strong>7</strong>,8,<strong>9</strong>]]
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<strong>Output:</strong> 25
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<strong>Explanation: </strong>Diagonals sum: 1 + 5 + 9 + 3 + 7 = 25
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Notice that element mat[1][1] = 5 is counted only once.
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> mat = [[<strong>1</strong>,1,1,<strong>1</strong>],
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[1,<strong>1</strong>,<strong>1</strong>,1],
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[1,<strong>1</strong>,<strong>1</strong>,1],
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[<strong>1</strong>,1,1,<strong>1</strong>]]
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<strong>Output:</strong> 8
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</pre>
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<p><strong>Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> mat = [[<strong>5</strong>]]
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<strong>Output:</strong> 5
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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>n == mat.length == mat[i].length</code></li>
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<li><code>1 <= n <= 100</code></li>
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<li><code>1 <= mat[i][j] <= 100</code></li>
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</ul>
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