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50 lines
1.6 KiB
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50 lines
1.6 KiB
HTML
<p>You are given an <strong>even</strong> integer <code>n</code>. You initially have a permutation <code>perm</code> of size <code>n</code> where <code>perm[i] == i</code> <strong>(0-indexed)</strong>.</p>
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<p>In one operation, you will create a new array <code>arr</code>, and for each <code>i</code>:</p>
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<ul>
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<li>If <code>i % 2 == 0</code>, then <code>arr[i] = perm[i / 2]</code>.</li>
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<li>If <code>i % 2 == 1</code>, then <code>arr[i] = perm[n / 2 + (i - 1) / 2]</code>.</li>
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</ul>
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<p>You will then assign <code>arr</code> to <code>perm</code>.</p>
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<p>Return <em>the minimum <strong>non-zero</strong> number of operations you need to perform on </em><code>perm</code><em> to return the permutation to its initial value.</em></p>
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<p> </p>
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<p><strong class="example">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> 1
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<strong>Explanation:</strong> perm = [0,1] initially.
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After the 1<sup>st</sup> operation, perm = [0,1]
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So it takes only 1 operation.
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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> n = 4
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<strong>Output:</strong> 2
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<strong>Explanation:</strong> perm = [0,1,2,3] initially.
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After the 1<sup>st</sup> operation, perm = [0,2,1,3]
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After the 2<sup>nd</sup> operation, perm = [0,1,2,3]
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So it takes only 2 operations.
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</pre>
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<p><strong class="example">Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> n = 6
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<strong>Output:</strong> 4
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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>2 <= n <= 1000</code></li>
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<li><code>n</code> is even.</li>
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</ul>
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