#include <bits/stdc++.h>

using namespace std;

#ifdef _DEBUG
#include "debug.h"
#else
#define debug(...) 42
#endif

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int tt;
  cin >> tt;
  while (tt--) {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    auto Works = [&](int L) {
      int at = 0;
      int used = 0;
      while (at < n) {
        if (s[at] == '0') {
          at += 1;
          continue;
        }
        used += 1;
        at += L;
      }
      return (used <= k);
    };
    int ret = *ranges::lower_bound(views::iota(1, n + 1), true, less{}, Works);
    cout << ret << '\n';
  }
  return 0;
}