Longest common subsequence
Return the length of the longest common subsequence of strings a and b. A subsequence keeps relative order but need not be contiguous; for example "abcde" and "ace" have LCS "ace" of length 3. Either string may be empty (answer 0). Strings can be up to ~1000 characters; an O(len(a)*len(b)) DP is expected, with O(min(len)) space achievable.
Implement
lcs_length(a: str, b: str) → intExamples
in
["abcde","ace"]out3What 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
["abcde","ace"]3not run yetsample