#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 2e5 + 9;
const int mod = 1e9 + 7;
#define eps 1e-5
#define inf 2e18
int n,k;
char s[N];

bool check(int x)
{
    int cnt=0,i;
    for(i=1;i<=n;++i)
    {
        if(s[i]=='1')
        {
            i = i + x - 1;
            cnt++;
        }
    } 
    if(cnt<=k) return false;
    return true;
}

void solve()
{
   cin>>n>>k;
   cin>>s+1;

    int l = 1, r = 2e5 + 100;
     while(l < r)
    {
        int mid = (l + r)/2;
        if(check(mid)) l = mid + 1;
        else r = mid;
    }
    cout<< l << '\n';
}

int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int _ = 1;  cin>>_;
    while (_--) solve();
    return 0;
}