#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, k;
  string s;
  cin >> n >> k >> s;
  auto check = [&](int w) {
    int c = 0;
    for (int i = 0; i < n; i += 1) {
      if (s[i] == '1') {
        c += 1;
        i += w - 1;
      }
    }
    return c <= k;
  };

  int l = 0, r = n + 1;
  while (r - l > 1) {
    int m = (l + r) / 2;
    if (check(m)) {
      r = m;
    } else {
      l = m;
    }
  }
  cout << r << "\n";
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
}