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## Tokitsukaze and Good 01-String (easy version) Codeforces Solution | Codeforces Problem Solution 2022

B1. Tokitsukaze and Good 01-String (easy version)
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

This is the easy version of the problem. The only difference between the two versions is that the harder version asks additionally for a minimum number of subsegments.

Tokitsukaze has a binary string $s$ of length $n$, consisting only of zeros and ones, $n$ is even.

Now Tokitsukaze divides $s$ into the minimum number of contiguous subsegments, and for each subsegment, all bits in each subsegment are the same. After that, $s$ is considered good if the lengths of all subsegments are even.

For example, if $s$ is "11001111", it will be divided into "11", "00" and "1111". Their lengths are $2$$2$$4$ respectively, which are all even numbers, so "11001111" is good. Another example, if $s$ is "1110011000", it will be divided into "111", "00", "11" and "000", and their lengths are $3$$2$$2$$3$. Obviously, "1110011000" is not good.

[Solution] Tokitsukaze and Good 01-String

Tokitsukaze and Two Colorful Tapes Codeforces Solution

Tokitsukaze and Permutations Codeforces Solution

Tokitsukaze wants to make $s$ good by changing the values of some positions in $s$. Specifically, she can perform the operation any number of times: change the value of ${s}_{i}$ to '0' or '1'($1\le i\le n$). Can you tell her the minimum number of operations to make $s$ good?

Input

The first contains a single positive integer $t$ ($1\le t\le 10\phantom{\rule{thinmathspace}{0ex}}000$) — the number of test cases.

For each test case, the first line contains a single integer $n$ ($2\le n\le 2\cdot {10}^{5}$) — the length of $s$, it is guaranteed that $n$ is even.

The second line contains a binary string $s$ of length $n$, consisting only of zeros and ones.

It is guaranteed that the sum of $n$ over all test cases does not exceed $2\cdot {10}^{5}$.

Output

For each test case, print a single line with one integer — the minimum number of operations to make $s$ good.