Skip to content

Latest commit

 

History

History
51 lines (47 loc) · 949 Bytes

1513. Number of Substrings With Only 1s.md

File metadata and controls

51 lines (47 loc) · 949 Bytes

Given a binary string s (a string consisting only of '0' and '1's).

Return the number of substrings with all characters 1's.

Since the answer may be too large, return it modulo 10^9 + 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.

Example 4:

Input: s = "000"
Output: 0

Constraints:

s[i] == '0' or s[i] == '1'
1 <= s.length <= 10^5
class Solution {
    public int numSub(String s) {
        int count=0;
        int res=0;
        for(int i=0;i<s.length();i++){
           count=s.charAt(i)=='1'?count+1:0;
           res=(res+count)%(int)(1e9+7); 
        }
        return res;
    }
}