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45 lines
1.6 KiB
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45 lines
1.6 KiB
HTML
<p>An <strong>n-bit gray code sequence</strong> is a sequence of <code>2<sup>n</sup></code> integers where:</p>
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<ul>
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<li>Every integer is in the <strong>inclusive</strong> range <code>[0, 2<sup>n</sup> - 1]</code>,</li>
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<li>The first integer is <code>0</code>,</li>
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<li>An integer appears <strong>no more than once</strong> in the sequence,</li>
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<li>The binary representation of every pair of <strong>adjacent</strong> integers differs by <strong>exactly one bit</strong>, and</li>
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<li>The binary representation of the <strong>first</strong> and <strong>last</strong> integers differs by <strong>exactly one bit</strong>.</li>
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</ul>
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<p>Given an integer <code>n</code>, return <em>any valid <strong>n-bit gray code sequence</strong></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> [0,1,3,2]
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<strong>Explanation:</strong>
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The binary representation of [0,1,3,2] is [00,01,11,10].
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- 0<u>0</u> and 0<u>1</u> differ by one bit
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- <u>0</u>1 and <u>1</u>1 differ by one bit
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- 1<u>1</u> and 1<u>0</u> differ by one bit
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- <u>1</u>0 and <u>0</u>0 differ by one bit
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[0,2,3,1] is also a valid gray code sequence, whose binary representation is [00,10,11,01].
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- <u>0</u>0 and <u>1</u>0 differ by one bit
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- 1<u>0</u> and 1<u>1</u> differ by one bit
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- <u>1</u>1 and <u>0</u>1 differ by one bit
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- 0<u>1</u> and 0<u>0</u> differ by one bit
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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 = 1
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<strong>Output:</strong> [0,1]
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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 <= 16</code></li>
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</ul>
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