import java.util.*;import java.io.*;

public class Main {
    public static void main(String[] args) {
        try {
            FastReader in = new FastReader();
            FastWriter out = new FastWriter();
            int testcases = 1;   testcases = in.nextInt();

            while (testcases-- > 0) {
               int siz = in.nextInt();
               int ops = in.nextInt();
               char[] word = in.next().toCharArray();
               PriorityQueue<Long> pq = new PriorityQueue<>(Comparator.reverseOrder());
               int curr = 0;
                for (char c : word) {
                    if (c == '1') {
                        curr++;
                    } else {
                        if(curr != 0) pq.add((long) curr);
                        curr = 0;
                    }
                }
                if(curr != 0) pq.add((long) curr);
//                out.print(pq);
               while(pq.size() > 1 && ops > 0) {
                   long first = pq.poll();
                   long second = pq.isEmpty() ? 0 : pq.poll();
                   pq.offer(first+second);
                   ops--;
               }
               out.println(pq.peek());
            }
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
            return;
        }
    }/* <Fast---reader> */ static class FastReader { BufferedReader br; StringTokenizer st; public FastReader() { br = new BufferedReader(new InputStreamReader(System.in)); } String next() { while (st == null || !st.hasMoreTokens()) { try { st = new StringTokenizer(br.readLine()); } catch (Exception e) { e.printStackTrace(); } } return st.nextToken(); } int nextInt() { return Integer.parseInt(next()); } long nextLong() { return Long.parseLong(next()); } double nextDouble() { return Double.parseDouble(next()); } String nextLine() { String str = ""; try { str = br.readLine().trim(); } catch (Exception e) { e.printStackTrace(); } return str; } }
    /* <Fast---writer> */ static class FastWriter { private final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out)); public void print(Object object) throws IOException { bw.append("" + object); } public void println() throws IOException { bw.append("\n"); } public void println(Object object) throws IOException { print(object); bw.append("\n"); } public void close() throws IOException { bw.close(); } }

}