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

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int t;
	cin >> t;
	while (t--) {
		int n, k;
		string s;
		cin >> n >> k >> s;
		int l = 0, r = n;
		while (r - l > 1) {
			int m = (l + r) / 2;
			int cnt = 0;
			for (int i = 0; i < n; i++) {
				if (s[i] == '1') {
					i += m - 1;
					cnt++;
				}
			}
			if (cnt <= k) {
				r = m;
			}
			else {
				l = m;
			}
		}
		cout << r << "\n";
	}
	return 0;
}