Solution (leetcode-in-java 1.19 API)

java.lang.Object
- g0901_1000.s0940_distinct_subsequences_ii.Solution

```
public class Solution
extends Object
```
940 - Distinct Subsequences II.
Hard

Given a string s, return the number of distinct non-empty subsequences of s. Since the answer may be very large, return it modulo 10⁹ + 7.

A subsequence of a string is a new string that is formed from the original string by deleting some (can be none) of the characters without disturbing the relative positions of the remaining characters. (i.e., "ace" is a subsequence of "abcde" while "aec" is not.

Example 1:

Input: s = “abc”

Output: 7

Explanation: The 7 distinct subsequences are “a”, “b”, “c”, “ab”, “ac”, “bc”, and “abc”.

Example 2:

Input: s = “aba”

Output: 6

Explanation: The 6 distinct subsequences are “a”, “b”, “ab”, “aa”, “ba”, and “aba”.

Example 3:

Input: s = “aaa”

Output: 3

Explanation: The 3 distinct subsequences are “a”, “aa” and “aaa”.

Constraints:
- 1 <= s.length <= 2000
- s consists of lowercase English letters.

- Constructor Summary
  
  Constructors
  Constructor Description
  
  Solution()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  int distinctSubseqII(String str)
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- Solution
```
public Solution()
```

Method Detail

distinctSubseqII

public int distinctSubseqII(String str)