#include <bits/stdc++.h>
using namespace std;
#define int long long
int32_t main() {
int t;
cin >> t;
for(int q=0; q<t; ++q) {
int length, k;
cin >> length >> k;
int vec[length];
string str;
cin >> str;
for(int i=0; i<length; ++i) vec[i]=str[i]-48;
multiset<int> consecutive_ones;
int cnt=0, flag=0;
for(auto elem:vec) {
if(elem==1) {
cnt++;
flag=1;
}
else if(elem==0 && flag && cnt) consecutive_ones.insert(cnt), cnt=0;
}
if(cnt) consecutive_ones.insert(cnt), cnt=0;
int ans=0;
vector<int> vec1;
for(auto elem : consecutive_ones) vec1.push_back(elem);
reverse(vec1.begin(), vec1.end());
for(auto elem : vec1) {if(k+1) {ans+=elem; k--;}}
cout << ans << endl;
}
return 0;
}