Coding contest, problem 2 of 5
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Longest arithmetic subsequence
Given an integer array and an integer difference d, return the length of the longest subsequence (elements in original order, not necessarily contiguous) that forms an arithmetic sequence with common difference exactly d. The array has at most 100000 elements with values in [-10000, 10000].
Implement
longest_arith_subseq(arr: list[int], d: int) → intExamples
in
[[1,2,3,4],1]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 25 min
solution.py
InputExpectedGot
[[1,2,3,4],1]4not run yetsample