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36 lines
1.3 KiB
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36 lines
1.3 KiB
HTML
<p>Given a <strong>0-indexed</strong> integer array <code>nums</code> of length <code>n</code> and an integer <code>k</code>, return <em>the <strong>number of pairs</strong></em> <code>(i, j)</code> <em>such that:</em></p>
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<ul>
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<li><code>0 <= i < j <= n - 1</code> <em>and</em></li>
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<li><code>nums[i] * nums[j]</code> <em>is divisible by</em> <code>k</code>.</li>
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</ul>
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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> nums = [1,2,3,4,5], k = 2
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<strong>Output:</strong> 7
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<strong>Explanation:</strong>
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The 7 pairs of indices whose corresponding products are divisible by 2 are
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(0, 1), (0, 3), (1, 2), (1, 3), (1, 4), (2, 3), and (3, 4).
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Their products are 2, 4, 6, 8, 10, 12, and 20 respectively.
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Other pairs such as (0, 2) and (2, 4) have products 3 and 15 respectively, which are not divisible by 2.
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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> nums = [1,2,3,4], k = 5
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<strong>Output:</strong> 0
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<strong>Explanation:</strong> There does not exist any pair of indices whose corresponding product is divisible by 5.
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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 <= nums.length <= 10<sup>5</sup></code></li>
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<li><code>1 <= nums[i], k <= 10<sup>5</sup></code></li>
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</ul>
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