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CF1750B.Maximum Substring
Maximum Substring
A binary string is a string consisting only of the characters 0 and 1. You are given a binary string .
For some non-empty substring of string containing characters 0 and characters 1, define its cost as:
- , if and ;
- , if and ;
- , if and .
Given a binary string of length , find the maximum cost across all its non-empty substrings.
A string is a substring of a string if can be obtained from by deletion of several (possibly, zero or all) characters from the beginning and several (possibly, zero or all) characters from the end.
Input
Each test consists of multiple test cases. The first line contains a single integer () — the number of test cases. The description of test cases follows.
The first line of each test case contains a single integer () — the length of the string .
The second line of each test case contains a binary string of length .
It is guaranteed that the sum of over all test cases does not exceed .
Output
For each test case, print a single integer — the maximum cost across all substrings.
Note
In the first test case, we can take a substring . It contains characters 1 and characters 0. So , and its cost is .
In the second test case, we can take the whole string. It contains characters 1 and characters 0. So , and its cost is .
In the third test case, we can can take a substring and its cost is .
In the fourth test case, we can take the whole string and cost is .
In the fifth test case, we can take a substring and its cost is .
In the sixth test case, we can only take the substring and its cost is .
Samples
6
5
11100
7
1100110
6
011110
7
1001010
4
1000
1
0
9
12
16
12
9
1
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