#include <bits/stdc++.h>
#define rep(i,j,k) for(int i=(j);i<=(k);i++)
#define per(i,j,k) for(int i=(j);i>=(k);i--)
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define db double
#define ldb long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mkp make_pair
#define eb emplace_back
#define SZ(S) (int)S.size()
//#define mod 998244353
//#define mod 1000000007
#define inf 0x3f3f3f3f
#define linf 0x3f3f3f3f3f3f3f3f
using namespace std;

template <class T>
void chkmax(T &x,T y){
	if(x < y) x = y;
}

template <class T>
void chkmin(T &x,T y){
	if(x > y) x = y;
}

inline int popcnt(int x){
	return __builtin_popcount(x);
}

inline int ctz(int x){
	return __builtin_ctz(x);
}


/*ll power(ll p,int k = mod - 2){
	ll ans = 1;
	while(k){
		if(k % 2 == 1) ans = ans * p % mod;
		p = p * p % mod;
		k /= 2;	
	}
	return ans;
}*/
int T,n,m,L;
char s[200005];

int ans[200005];
void solve(){
	scanf("%d%d",&n,&m);
	scanf("%s",s + 1);
	if(n < m) swap(n,m);
	int j = m,bst = 0;
	rep(k,1,n){
		if(s[m + k] == '1'){
			bst = k;
			continue;
		}
		while(j && s[j] == '0') j--;
		if(!j) break;
		if(m - j > n - k) break;
		j--;
		bst = k;
	}
//	printf("%d ",bst);
	L = 0;
	int lim = m + bst;
	per(k,lim,1){
		if(s[k] == '1'){
			if(bst) bst--;
			else ans[++L]++;
		}else{
			++L;
		}
	}
//	printf("L=%d\n",L);
	assert(L == m);
//	rep(i,1,L) printf("%d",ans[i]);
//	printf("\n");
	L = 0;
	per(k,n + m,lim + 1) ans[++L] += s[k] - '0';
	rep(k,1,lim - m) ans[++L]++;

	rep(k,1,L){
		if(ans[k] >= 2){
			ans[k] -= 2;
			ans[k + 1]++;
		}
		if(k == L && ans[k + 1]) L++;
	}
	while(L && !ans[L]) L--;
	if(!L){
		printf("0");
	}else{
		per(i,L,1){
			printf("%d",ans[i]);
			ans[i] = 0;
		}		
	}
	printf("\n");
}

int main(){
//	freopen("test.in","r",stdin);
	scanf("%d",&T);
	while(T--) solve();
	return 0;
}