{ "data": { "question": { "questionId": "2122", "questionFrontendId": "1995", "boundTopicId": null, "title": "Count Special Quadruplets", "titleSlug": "count-special-quadruplets", "content": "

Given a 0-indexed integer array nums, return the number of distinct quadruplets (a, b, c, d) such that:

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Example 1:

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\nInput: nums = [1,2,3,6]\nOutput: 1\nExplanation: The only quadruplet that satisfies the requirement is (0, 1, 2, 3) because 1 + 2 + 3 == 6.\n
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Example 2:

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\nInput: nums = [3,3,6,4,5]\nOutput: 0\nExplanation: There are no such quadruplets in [3,3,6,4,5].\n
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Example 3:

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\nInput: nums = [1,1,1,3,5]\nOutput: 4\nExplanation: The 4 quadruplets that satisfy the requirement are:\n- (0, 1, 2, 3): 1 + 1 + 1 == 3\n- (0, 1, 3, 4): 1 + 1 + 3 == 5\n- (0, 2, 3, 4): 1 + 1 + 3 == 5\n- (1, 2, 3, 4): 1 + 1 + 3 == 5\n
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Constraints:

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