**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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