cpp-flashcards/org/study_deck_02/dsa/2-d-dynamic-programming/0115-distinct-subsequences.org

#+ANKI_DECK: study_deck_02
* TODO 0115. Distinct Subsequences :hard:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0115. Distinct Subsequences][0115. Distinct Subsequences]]
:END:

Given two strings s and t, return the number of distinct subsequences of s which equals t.

The test cases are generated so that the answer fits on a 32-bit signed integer.

*Example 1:*


#+begin_src
Input: s = "rabbbit", t = "rabbit"
Output: 3
Explanation:
As shown below, there are 3 ways you can generate "rabbit" from s.
rabbbit
rabbbit
rabbbit
#+end_src


*Example 2:*


#+begin_src
Input: s = "babgbag", t = "bag"
Output: 5
Explanation:
As shown below, there are 5 ways you can generate "bag" from s.
babgbag
babgbag
babgbag
babgbag
babgbag
#+end_src


*Constraints:*

 - ~1 <= s.length, t.length <= 1000~

 - ~s~ and ~t~ consist of English letters.

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python :lc-problem 115 :lc-lang python3
class Solution:
    def numDistinct(self, s: str, t: str) -> int:
#+end_src

** TODO C++
#+begin_src cpp :lc-problem 115
class Solution {
public:
    int numDistinct(string s, string t) {
        
    }
};
#+end_src