B"You are given a binary string s of length n . We define a maximal substring as a substring that cannot be extended while keeping all elements equal. For example, in the string 11000111 there are three maximal substrings: 11 , 000 and 111 . In one operation, you can select two maximal adjacent substrings. Since they are maximal and adjacent, it's easy to see their elements must have different values. Let a be the length of the sequence of ones and b be the length of the sequence of zeros. Then do the following: As an example, for 1110000 we make it 0000000 , for 0011 we make it 1111 . We call a string being good if it can be turned into 1111...1111 using the aforementioned operation any number of times (possibly, zero). Find the number of good substrings among all frac{n(n+1)}{2} non-empty substrings of s . Each test consists of multiple test cases. The first line contains a single integer t ( 1 <= q t <= q 10^5 ) -- the number of test cases. The description of test cases follows. The first line of each test case contains n ( 1 <= n <= 2 cdot 10^5 ) -- the length of the string s . The second line of each test case contains the binary string s of length n . It is guaranteed that sum of n across all test cases doesn't exceed 2 cdot 10^5 . For each test case, print a single integer -- the number of good substrings. Let's define a substring from index l to index r as [l, r] . For the first test case, the good substrings are: In the second test case, all substrings are good except [2,2] . In the third test case, all substrings are good. "...