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37 lines
1.2 KiB
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37 lines
1.2 KiB
HTML
<p>You have a list <code>arr</code> of all integers in the range <code>[1, n]</code> sorted in a strictly increasing order. Apply the following algorithm on <code>arr</code>:</p>
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<ul>
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<li>Starting from left to right, remove the first number and every other number afterward until you reach the end of the list.</li>
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<li>Repeat the previous step again, but this time from right to left, remove the rightmost number and every other number from the remaining numbers.</li>
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<li>Keep repeating the steps again, alternating left to right and right to left, until a single number remains.</li>
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</ul>
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<p>Given the integer <code>n</code>, return <em>the last number that remains in</em> <code>arr</code>.</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 = 9
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<strong>Output:</strong> 6
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<strong>Explanation:</strong>
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arr = [<u>1</u>, 2, <u>3</u>, 4, <u>5</u>, 6, <u>7</u>, 8, <u>9</u>]
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arr = [2, <u>4</u>, 6, <u>8</u>]
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arr = [<u>2</u>, 6]
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arr = [6]
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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 <= 10<sup>9</sup></code></li>
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</ul>
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