Count Substrings With All 1s - Google Top Interview Questions

Problem Statement :

```You are given a string s containing "1"s and "0"s.
Return the number of substrings that contain only "1"s. Mod the result by 10 ** 9 + 7.

Constraints

0 ≤ n ≤ 100,000 where n is the length of s

Example 1

Input

s = "111001"

Output

7

Explanation

Here are all the substrings containing only "1"s:

"1"

"1"

"1"

"1"

"11"

"11"

"111"```

Solution :

```                        ```Solution in C++ :

int solve(string s) {
int i = 0, ans = 0, mod = 1e9 + 7;
for (int j = 0; j < s.length(); j++) {
if (s[j] == '0')
i = j + 1;
else
ans = (ans + j - i + 1) % mod;
}
return ans;
}```
```

```                        ```Solution in Java :

import java.util.*;

class Solution {
public int solve(String s) {
int tempResult = 0;
int result = 0;
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == '1') {
tempResult++;
} else {
while (tempResult > 0) {
result += tempResult;
tempResult--;
}
}
}
while (tempResult > 0) {
result += tempResult;
tempResult--;
}

return result;
}
}```
```

```                        ```Solution in Python :

class Solution:
def solve(self, s):
a = 0
count = 0
for i in range(len(s)):
if s[i] == "0":
a = 0
else:
a += 1
count += a
return count```
```

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