#include <cstdio>
#include <algorithm>
using namespace std;
int read(){
	char c=getchar();int x=0;
	while(c<48||c>57) c=getchar();
	do x=x*10+(c^48),c=getchar();
	while(c>=48&&c<=57);
	return x;
}
const int N=2000003;
int n,m,rk;
bool s[N],t[N],res[N];
void solve(){
	n=read();m=read();rk=0;
	char cc=getchar();
	while(cc!=48&&cc!=49) cc=getchar();
	for(int i=1;i<=n+m;++i) s[i]=cc^48,cc=getchar();
	if(n<m) swap(n,m);
	int ps=m,lim=n+m;
	for(int i=m+1;i<=n+m;++i)
		if(!s[i]){
			while(ps&&!s[ps]) --ps;
			if(!ps||n+ps<i){lim=i-1;break;}
			s[ps]=0;
		}
	for(int i=1;i<=lim-m;++i) t[++rk]=1;
	for(int i=lim+1;i<=n+m;++i) t[++rk]=s[i];
	reverse(s+1,s+m+1);
	reverse(t+1,t+n+1);
	for(int i=m+1;i<=n+m+1;++i) s[i]=0;
	for(int i=n+1;i<=n+m+1;++i) t[i]=0;
	int len=0;
	for(int i=1,carry=0;i<=n||i<=m||carry;++i){
		len=i;
		carry+=s[i]+t[i];
		res[i]=carry&1;
		carry>>=1;
	}
	while(len&&!res[len]) --len;
	if(len){
		for(int i=len;i;--i) putchar(res[i]^48);
		putchar('\n');
	}
	else puts("0");
}
int main(){
	int tc=read();
	while(tc--) solve();
	return 0;
}