{ "data": { "question": { "questionId": "376", "questionFrontendId": "376", "boundTopicId": null, "title": "Wiggle Subsequence", "titleSlug": "wiggle-subsequence", "content": "

A wiggle sequence is a sequence where the differences between successive numbers strictly alternate between positive and negative. The first difference (if one exists) may be either positive or negative. A sequence with one element and a sequence with two non-equal elements are trivially wiggle sequences.

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A subsequence is obtained by deleting some elements (possibly zero) from the original sequence, leaving the remaining elements in their original order.

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Given an integer array nums, return the length of the longest wiggle subsequence of nums.

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Example 1:

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\nInput: nums = [1,7,4,9,2,5]\nOutput: 6\nExplanation: The entire sequence is a wiggle sequence with differences (6, -3, 5, -7, 3).\n
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Example 2:

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\nInput: nums = [1,17,5,10,13,15,10,5,16,8]\nOutput: 7\nExplanation: There are several subsequences that achieve this length.\nOne is [1, 17, 10, 13, 10, 16, 8] with differences (16, -7, 3, -3, 6, -8).\n
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Example 3:

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\nInput: nums = [1,2,3,4,5,6,7,8,9]\nOutput: 2\n
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Constraints:

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Follow up: Could you solve this in O(n) time?

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C# 10 with .NET 6 runtime

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