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41 lines
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41 lines
1.5 KiB
HTML
<p>An integer array <code>original</code> is transformed into a <strong>doubled</strong> array <code>changed</code> by appending <strong>twice the value</strong> of every element in <code>original</code>, and then randomly <strong>shuffling</strong> the resulting array.</p>
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<p>Given an array <code>changed</code>, return <code>original</code><em> if </em><code>changed</code><em> is a <strong>doubled</strong> array. If </em><code>changed</code><em> is not a <strong>doubled</strong> array, return an empty array. The elements in</em> <code>original</code> <em>may be returned in <strong>any</strong> order</em>.</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> changed = [1,3,4,2,6,8]
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<strong>Output:</strong> [1,3,4]
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<strong>Explanation:</strong> One possible original array could be [1,3,4]:
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- Twice the value of 1 is 1 * 2 = 2.
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- Twice the value of 3 is 3 * 2 = 6.
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- Twice the value of 4 is 4 * 2 = 8.
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Other original arrays could be [4,3,1] or [3,1,4].
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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> changed = [6,3,0,1]
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<strong>Output:</strong> []
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<strong>Explanation:</strong> changed is not a doubled array.
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</pre>
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<p><strong>Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> changed = [1]
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<strong>Output:</strong> []
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<strong>Explanation:</strong> changed is not a doubled array.
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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 <= changed.length <= 10<sup>5</sup></code></li>
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<li><code>0 <= changed[i] <= 10<sup>5</sup></code></li>
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</ul>
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