Solution (leetcode-in-java 1.19 API)

java.lang.Object
- g1501_1600.s1513_number_of_substrings_with_only_1s.Solution

```
public class Solution
extends Object
```
1513 - Number of Substrings With Only 1s.
Medium

Given a binary string s, return the number of substrings with all characters 1’s. Since the answer may be too large, return it modulo 10⁹ + 7.

Example 1:

Input: s = “0110111”

Output: 9

Explanation: There are 9 substring in total with only 1’s characters. “1” -> 5 times. “11” -> 3 times. “111” -> 1 time.

Example 2:

Input: s = “101”

Output: 2

Explanation: Substring “1” is shown 2 times in s.

Example 3:

Input: s = “111111”

Output: 21

Explanation: Each substring contains only 1’s characters.

Constraints:
- 1 <= s.length <= 10⁵
- s[i] is either '0' or '1'.

- Constructor Summary
  
  Constructors
  Constructor Description
  
  Solution()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  int numSub(String s)
  - 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
- numSub
```
public int numSub(String s)
```