#include <bits/stdc++.h>
using namespace std;
 
// Speed
#define fast_io ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
 
// Typedefs
#define int long long
#define pb push_back
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((int)(x).size())
#define endl '\n'
 
// Loops
#define rep(i,a,b) for(int i=a;i<b;++i)
#define each(x, a) for (auto &x : a)
 
void solve() {
    int n,k;
    cin>>n>>k;
    string s;
    cin>>s;
    int count=0,b=0;
    rep(i,0,n){
    	if(s[i]==1) {
    		b=k;
    	}
    	else if(s[i]==0 && b!=0){
    		b--;
    	}
    	else count++;
    }
    cout<<count<<endl;
}
 
int32_t main() {
    fast_io;
    int t;
    cin >> t;
    while (t--) solve();
    return 0;
}
 

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NAo0IDEKMTAwMQozIDMKMDAwCjMgMQowMDEKOCAyCjAxMDAwMTAxCg==

4
4 1
1001
3 3
000
3 1
001
8 2
01000101