bit-even-count-on-rotation.cpp

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ull unsigned long long
#define ff first
#define ss second
#define mp make_pair
#define pb push_back
const int N = 2e5 + 11;

void solve() {
	int len;
	cin >> len;
	int zero_count = 0;

	string bi_str;
	cin >> bi_str;

	for (int i = 0; i < bi_str.size(); i++) 
		if (bi_str[i] == '0')zero_count++;

	cout << zero_count << endl;
}

int main() {
	freopen("input.txt", "r", stdin);
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int no_of_test_cases = 1;
	cin >> no_of_test_cases;
	while (no_of_test_cases--)solve();
	return 0;
}