Longest arithmetic progression subsequence
Given an integer array nums, return the length of the longest subsequence whose consecutive elements form an arithmetic progression (constant difference). A single element counts as length 1. 1 <= len(nums) <= 1000, -10^4 <= nums[i] <= 10^4.
Implement
longest_arith_subseq(nums: list[int]) → intExamples
in
[[3,6,9,12]]out4What a strong answer looks like
State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
0:00 of about 30 min
solution.py
InputExpectedGot
[[3,6,9,12]]4not run yetsample