#include <bits/stdc++.h>
void solve();
// struct __{ __() { freopen("partition.in", "r", stdin), freopen("partition.out", "w", stdout); } } ___;
int main() { int T; scanf("%d", &T); while (T--) solve(); }
using namespace std;
#define N 2000010
int n, m, k, ca, cb, a[N], b[N], c[N];
char s[N];
void solve() {
    scanf("%d%d%s", &n, &m, s + 1);
    ca = n, cb = m, k = n + m;
    for(int i = 1; i <= k + 10; i++) a[i] = b[i] = 0;
    for(int i = 1; i <= k; i++) s[i] -= '0';
    for(int i = 1; i <= k; i++) c[i] = c[i - 1] + s[i];
    for(int i = 1; i <= k; i++) {
        bool flag = 0;
        if(!ca) flag = 1; 
        else if(!cb) flag = 0;
        else if(ca <= cb) flag = 0;
        else flag = 1;

        if(flag) swap(a, b), swap(ca, cb);

        if(s[i] == 0) {
            a[ca--] = s[i];
        } else {
            if(c[k - ca] - c[i] >= cb - ca) {
                a[ca--] = s[i];
            } else {
                b[cb--] = s[i];
            }
        }

        if(flag) swap(a, b), swap(ca, cb);
    }
    int len = max({n, m, 1});
    for(int i = 1; i <= len; i++) {
        a[i] += b[i];
        if(a[i] >= 2) {
            a[i + 1] += a[i] / 2;
            a[i] %= 2;
            if(i + 1 > len) len = i + 1;
        }
    }
    while(a[len] == 0 && len > 1) len--;
    reverse(a + 1, a + len + 1);
    for(int i = 1; i <= len; i++) printf("%d", a[i]);
    printf("\n");
}