235. Distinct Subsequences
Hard · Dynamic Programming
Given strings `s` and `t`, return the number of distinct subsequences of `s` which equals `t`.
Examples
Example 1 Input: s="rabbbit", t="rabbit" Output: 3 Explanation: Three ways to choose which 'b' to remove
Constraints
- 1 ≤ s.length ≤ 1000, 1 ≤ t.length ≤ 1000