Distinct palindromic subsequences
Given a string s, count the number of distinct non-empty palindromic SUBSEQUENCES in s, modulo 1000000007. Subsequences are distinguished by their character content (equal strings count once), not by index. 1 <= len(s) <= 1000, lowercase letters. Example: 'bccb' has palindromic subsequences b, c, cc, bb, bcb, bccb = 6.
Implement
count_distinct_palindromic_subseq(s: str) → intExamples
in
["bccb"]out6What 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 35 min
solution.py
InputExpectedGot
["bccb"]6not run yetsample