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43 lines
1.3 KiB
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<p>Given an array <code>arr</code> of integers, check if there exists two integers <code>N</code> and <code>M</code> such that <code>N</code> is the double of <code>M</code> ( i.e. <code>N = 2 * M</code>).</p>
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<p>More formally check if there exists two indices <code>i</code> and <code>j</code> such that :</p>
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<ul>
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<li><code>i != j</code></li>
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<li><code>0 <= i, j < arr.length</code></li>
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<li><code>arr[i] == 2 * arr[j]</code></li>
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</ul>
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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> arr = [10,2,5,3]
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<strong>Output:</strong> true
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<strong>Explanation:</strong> N<code> = 10</code> is the double of M<code> = 5</code>,that is, <code>10 = 2 * 5</code>.
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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> arr = [7,1,14,11]
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<strong>Output:</strong> true
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<strong>Explanation:</strong> N<code> = 14</code> is the double of M<code> = 7</code>,that is, <code>14 = 2 * 7</code>.
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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> arr = [3,1,7,11]
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<strong>Output:</strong> false
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<strong>Explanation:</strong> In this case does not exist N and M, such that N = 2 * M.
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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>2 <= arr.length <= 500</code></li>
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<li><code>-10^3 <= arr[i] <= 10^3</code></li>
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</ul>
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