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:
    def numSub(self, s: str) -> int:
        num_lst = []
        ans = 0
        temp = 0
        
        for n in s:
            if n == '1':
                temp += 1
                
            if n == '0' and temp != 0:
                num_lst.append(temp)
                temp = 0
                
        if temp != 0: num_lst.append(temp) 
        
        if len(num_lst) == 0: return 0
        
        for num in num_lst:
            while num != 0:
                ans += num
                num -= 1
                
        return ans % ((10**9) + 7)
class Solution:
    def numSub(self, s: str) -> int:
        num_lst = []
        ans = 0
        temp = 0
        
        for n in s:
            if n == '1':
                temp += 1
                
            if n == '0' and temp != 0:
                num_lst.append(temp)
                temp = 0
                
        if temp != 0: num_lst.append(temp) 
        
        if len(num_lst) == 0: return 0
        
        for num in num_lst:
            while num != 0:
                ans += num
                num -= 1
                
        return ans % ((10**9) + 7)