{ "data": { "question": { "questionId": "2280", "questionFrontendId": "2179", "boundTopicId": null, "title": "Count Good Triplets in an Array", "titleSlug": "count-good-triplets-in-an-array", "content": "

You are given two 0-indexed arrays nums1 and nums2 of length n, both of which are permutations of [0, 1, ..., n - 1].

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A good triplet is a set of 3 distinct values which are present in increasing order by position both in nums1 and nums2. In other words, if we consider pos1v as the index of the value v in nums1 and pos2v as the index of the value v in nums2, then a good triplet will be a set (x, y, z) where 0 <= x, y, z <= n - 1, such that pos1x < pos1y < pos1z and pos2x < pos2y < pos2z.

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Return the total number of good triplets.

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Example 1:

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\nInput: nums1 = [2,0,1,3], nums2 = [0,1,2,3]\nOutput: 1\nExplanation: \nThere are 4 triplets (x,y,z) such that pos1x < pos1y < pos1z. They are (2,0,1), (2,0,3), (2,1,3), and (0,1,3). \nOut of those triplets, only the triplet (0,1,3) satisfies pos2x < pos2y < pos2z. Hence, there is only 1 good triplet.\n
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Example 2:

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\nInput: nums1 = [4,0,1,3,2], nums2 = [4,1,0,2,3]\nOutput: 4\nExplanation: The 4 good triplets are (4,0,3), (4,0,2), (4,1,3), and (4,1,2).\n
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Constraints:

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