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37 lines
1.2 KiB
HTML
37 lines
1.2 KiB
HTML
<p>You are given the head of a singly linked-list. The list can be represented as:</p>
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<pre>
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L<sub>0</sub> → L<sub>1</sub> → … → L<sub>n - 1</sub> → L<sub>n</sub>
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</pre>
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<p><em>Reorder the list to be on the following form:</em></p>
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<pre>
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L<sub>0</sub> → L<sub>n</sub> → L<sub>1</sub> → L<sub>n - 1</sub> → L<sub>2</sub> → L<sub>n - 2</sub> → …
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</pre>
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<p>You may not modify the values in the list's nodes. Only nodes themselves may be changed.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/03/04/reorder1linked-list.jpg" style="width: 422px; height: 222px;" />
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<pre>
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<strong>Input:</strong> head = [1,2,3,4]
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<strong>Output:</strong> [1,4,2,3]
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</pre>
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<p><strong>Example 2:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/03/09/reorder2-linked-list.jpg" style="width: 542px; height: 222px;" />
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<pre>
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<strong>Input:</strong> head = [1,2,3,4,5]
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<strong>Output:</strong> [1,5,2,4,3]
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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>The number of nodes in the list is in the range <code>[1, 5 * 10<sup>4</sup>]</code>.</li>
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<li><code>1 <= Node.val <= 1000</code></li>
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</ul>
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