Solution: Count the Number of Good Subsequences
Explore how to count good subsequences in a string where character frequencies match using dynamic programming. Understand calculating combinations with binomial coefficients and modular arithmetic. This lesson teaches how to optimize factorial calculations to efficiently solve the problem within O(N) time complexity.
We'll cover the following...
We'll cover the following...
Statement
Count and return the number of good subsequences in the given string s. You may return the modulo
A subsequence is a sequence formed from another sequence by deleting some or no elements while keeping the order of the remaining elements unchanged.
A good subsequence is a subsequence of a string if it is not empty and the frequency of each character is the same.
Constraints:
s.lengthswill only contain ...