Watch 10 video solutions for Longest Arithmetic Subsequence, a medium level problem involving Array, Hash Table, Binary Search. This walkthrough by NeetCode has 432,482 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
Given an array nums of integers, return the length of the longest arithmetic subsequence in nums.
Note that:
seq is arithmetic if seq[i + 1] - seq[i] are all the same value (for 0 <= i < seq.length - 1).
Example 1:
Input: nums = [3,6,9,12] Output: 4 Explanation: The whole array is an arithmetic sequence with steps of length = 3.
Example 2:
Input: nums = [9,4,7,2,10] Output: 3 Explanation: The longest arithmetic subsequence is [4,7,10].
Example 3:
Input: nums = [20,1,15,3,10,5,8] Output: 4 Explanation: The longest arithmetic subsequence is [20,15,10,5].
Constraints:
2 <= nums.length <= 10000 <= nums[i] <= 500