#include<bits/stdc++.h>
#define pt putchar
using namespace std;
typedef long long ll;
int read();void write(int);
const int N=1e6+5;
int n,m;
int a[N*2];
int ans[N*2];

void solve(){
	n=read();m=read();
	if(n<m)swap(n,m);
	int lim=n+1;
	for(int i=0;i<=lim;i++)
		ans[i]=0;
	char c=getchar();
	while(c!='0'&&c!='1')c=getchar();
	for(int i=1;i<=n+m;i++){
		a[i]=c-'0';
		c=getchar();
	}
	int la=m;
	while(la>=1&&!a[la])la--;
	for(int p=m;p<n+m;p++){
		if(!la)break;
		if(a[p+1]==0){
			if(m-la>=n+m-p-1){
				break;
			}
			ans[m-la]--;
			ans[n+m-p-1]++;
			//printf("%d:%d %d\n",p,m-la,n+m-p-1);
			
			la--;
			while(la>=1&&!a[la])la--;
			if(!la)break;
		}
	}
	for(int i=1;i<=m;i++){
		ans[m-i]+=a[i];
	}
	for(int i=1;i<=n;i++){
		ans[n-i]+=a[i+m];
	}
	for(int i=0;i<=lim;i++){
		int ji=ans[i]/2;
		if(ans[i]<=-1)ji++;
		ans[i]=(ans[i]%2+2)%2;
		ans[i+1]+=ji;
	}
	int i=lim;
	while(i>=1&&!ans[i])i--;
	for(;i>=0;i--){
		pt(ans[i]+'0');
	}pt('\n');
}

int main(){//fc partition.out example2.out
	//freopen("example2.in","r",stdin);freopen("partition.out","w",stdout);
	int T=read();
	while(T--){
		solve();
	}
	return 0;
}
/*
7 4
10111011111

1
7 6
0001010011011

*/

int read(){
	int x=0,f=1;
	char c='A';
	while(c<'0'||c>'9'){
		c=getchar();
		if(c=='-')f=-f;
	}
	while(c>='0'&&c<='9')x=x*10+c-'0',c=getchar();
	return x*f;
}
void write(int x){
	if(x<0){
		pt('-');
		x=-x;
	}
	if(x>9){
		write(x/10);
	}
	pt(x%10+'0');
}