{ "data": { "question": { "questionId": "2848", "questionFrontendId": "2741", "boundTopicId": null, "title": "Special Permutations", "titleSlug": "special-permutations", "content": "

You are given a 0-indexed integer array nums containing n distinct positive integers. A permutation of nums is called special if:

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Return the total number of special permutations. As the answer could be large, return it modulo 109 + 7.

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Example 1:

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\nInput: nums = [2,3,6]\nOutput: 2\nExplanation: [3,6,2] and [2,6,3] are the two special permutations of nums.\n
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Example 2:

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\nInput: nums = [1,4,3]\nOutput: 2\nExplanation: [3,1,4] and [4,1,3] are the two special permutations of nums.\n
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Constraints:

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