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38 lines
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38 lines
1.2 KiB
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<p>Suppose you have <code>n</code> integers labeled <code>1</code> through <code>n</code>. A permutation of those <code>n</code> integers <code>perm</code> (<strong>1-indexed</strong>) is considered a <strong>beautiful arrangement</strong> if for every <code>i</code> (<code>1 <= i <= n</code>), <strong>either</strong> of the following is true:</p>
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<ul>
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<li><code>perm[i]</code> is divisible by <code>i</code>.</li>
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<li><code>i</code> is divisible by <code>perm[i]</code>.</li>
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</ul>
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<p>Given an integer <code>n</code>, return <em>the <strong>number</strong> of the <strong>beautiful arrangements</strong> that you can construct</em>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> n = 2
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<strong>Output:</strong> 2
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<b>Explanation:</b>
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The first beautiful arrangement is [1,2]:
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- perm[1] = 1 is divisible by i = 1
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- perm[2] = 2 is divisible by i = 2
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The second beautiful arrangement is [2,1]:
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- perm[1] = 2 is divisible by i = 1
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- i = 2 is divisible by perm[2] = 1
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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> n = 1
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<strong>Output:</strong> 1
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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>1 <= n <= 15</code></li>
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</ul>
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