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36 lines
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36 lines
1.2 KiB
HTML
<p>Given a <strong>0-indexed</strong> integer array <code>nums</code> of size <code>n</code> and two integers <code>lower</code> and <code>upper</code>, return <em>the number of fair pairs</em>.</p>
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<p>A pair <code>(i, j)</code> is <b>fair </b>if:</p>
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<ul>
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<li><code>0 <= i < j < n</code>, and</li>
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<li><code>lower <= nums[i] + nums[j] <= upper</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 = [0,1,7,4,4,5], lower = 3, upper = 6
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<strong>Output:</strong> 6
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<strong>Explanation:</strong> There are 6 fair pairs: (0,3), (0,4), (0,5), (1,3), (1,4), and (1,5).
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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 = [1,7,9,2,5], lower = 11, upper = 11
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<strong>Output:</strong> 1
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<strong>Explanation:</strong> There is a single fair pair: (2,3).
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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><code>1 <= nums.length <= 10<sup>5</sup></code></li>
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<li><code>nums.length == n</code></li>
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<li><code><font face="monospace">-10<sup>9</sup></font> <= nums[i] <= 10<sup>9</sup></code></li>
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<li><code><font face="monospace">-10<sup>9</sup> <= lower <= upper <= 10<sup>9</sup></font></code></li>
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</ul>
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