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30 lines
976 B
HTML
30 lines
976 B
HTML
<p>An array is <strong>squareful</strong> if the sum of every pair of adjacent elements is a <strong>perfect square</strong>.</p>
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<p>Given an integer array nums, return <em>the number of permutations of </em><code>nums</code><em> that are <strong>squareful</strong></em>.</p>
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<p>Two permutations <code>perm1</code> and <code>perm2</code> are different if there is some index <code>i</code> such that <code>perm1[i] != perm2[i]</code>.</p>
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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 = [1,17,8]
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<strong>Output:</strong> 2
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<strong>Explanation:</strong> [1,8,17] and [17,8,1] are the valid permutations.
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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 = [2,2,2]
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<strong>Output:</strong> 1
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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 <= 12</code></li>
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<li><code>0 <= nums[i] <= 10<sup>9</sup></code></li>
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</ul>
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