Longest Arithmetic Subsequence
Given an array nums of integers, return the length of the longest arithmetic subsequence in nums.
Note that:
- A subsequence is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.
- A sequence
seqis arithmetic ifseq[i + 1] - seq[i]are all the same value for0 <= i < seq.length - 1.
Example 1
Input
nums = [3,6,9,12]Output
4The whole array is an arithmetic sequence with steps of length 3.
Example 2
Input
nums = [9,4,7,2,10]Output
3The longest arithmetic subsequence is [4,7,10].
Constraints
- 2 <= nums.length <= 1000
- 0 <= nums[i] <= 500