{ "data": { "question": { "questionId": "1038", "questionFrontendId": "996", "boundTopicId": null, "title": "Number of Squareful Arrays", "titleSlug": "number-of-squareful-arrays", "content": "

An array is squareful if the sum of every pair of adjacent elements is a perfect square.

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Given an integer array nums, return the number of permutations of nums that are squareful.

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Two permutations perm1 and perm2 are different if there is some index i such that perm1[i] != perm2[i].

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Example 1:

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\nInput: nums = [1,17,8]\nOutput: 2\nExplanation: [1,8,17] and [17,8,1] are the valid permutations.\n
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Example 2:

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\nInput: nums = [2,2,2]\nOutput: 1\n
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Constraints:

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