Distinct palindromic subsequences
Given a string s of lowercase letters (0 <= len(s) <= 1000), return the number of DISTINCT non-empty palindromic subsequences of s, modulo 1_000_000_007. Two subsequences are different if their resulting strings differ (distinct by value, not by index set).
Implement
count_palindromic_subsequences(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