{ "data": { "question": { "questionId": "905", "questionFrontendId": "873", "boundTopicId": null, "title": "Length of Longest Fibonacci Subsequence", "titleSlug": "length-of-longest-fibonacci-subsequence", "content": "

A sequence x1, x2, ..., xn is Fibonacci-like if:

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Given a strictly increasing array arr of positive integers forming a sequence, return the length of the longest Fibonacci-like subsequence of arr. If one does not exist, return 0.

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A subsequence is derived from another sequence arr by deleting any number of elements (including none) from arr, without changing the order of the remaining elements. For example, [3, 5, 8] is a subsequence of [3, 4, 5, 6, 7, 8].

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Example 1:

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\nInput: arr = [1,2,3,4,5,6,7,8]\nOutput: 5\nExplanation: The longest subsequence that is fibonacci-like: [1,2,3,5,8].
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Example 2:

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\nInput: arr = [1,3,7,11,12,14,18]\nOutput: 3\nExplanation: The longest subsequence that is fibonacci-like: [1,11,12], [3,11,14] or [7,11,18].
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Constraints:

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