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34 lines
1.4 KiB
HTML
34 lines
1.4 KiB
HTML
<p>There are <code>n</code> couples sitting in <code>2n</code> seats arranged in a row and want to hold hands.</p>
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<p>The people and seats are represented by an integer array <code>row</code> where <code>row[i]</code> is the ID of the person sitting in the <code>i<sup>th</sup></code> seat. The couples are numbered in order, the first couple being <code>(0, 1)</code>, the second couple being <code>(2, 3)</code>, and so on with the last couple being <code>(2n - 2, 2n - 1)</code>.</p>
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<p>Return <em>the minimum number of swaps so that every couple is sitting side by side</em>. A swap consists of choosing any two people, then they stand up and switch seats.</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> row = [0,2,1,3]
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<strong>Output:</strong> 1
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<strong>Explanation:</strong> We only need to swap the second (row[1]) and third (row[2]) person.
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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> row = [3,2,0,1]
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<strong>Output:</strong> 0
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<strong>Explanation:</strong> All couples are already seated side by side.
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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>2n == row.length</code></li>
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<li><code>2 <= n <= 30</code></li>
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<li><code>n</code> is even.</li>
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<li><code>0 <= row[i] < 2n</code></li>
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<li>All the elements of <code>row</code> are <strong>unique</strong>.</li>
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</ul>
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