#include <bits/stdc++.h>

#define fir first
#define sec second
#ifdef LOCAL
#define dbg(x) cerr << "In Line " << __LINE__ << " the " << #x << " = " << x << '\n';
#define dpi(x, y) cerr << "In Line " << __LINE__ << " the " << #x << " = " << x << " ; " << "the " << #y << " = " << y << '\n';
#define dbgf(fmt, args...) fprintf(stderr, fmt, ##args)
#else
#define dbg(x) void();
#define dpi(x, y) void();
#define dbgf(fmt, args...) void();
#endif

using namespace std;

using ll = long long;
using ull = unsigned long long;
using i128 = __int128_t;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using vi = vector<int>;
using vpii = vector<pii>;

bool Mbe;
constexpr int MOD = 998244353;
template<typename T> T add(T a, T b, T p = MOD) { return (a + b >= p) ? (a + b - p) : (a + b); }
template<typename T> T del(T a, T b, T p = MOD) { return (a - b < 0) ? (a - b + p) : (a - b); }
template<typename T> T mul(T a, T b, T p = MOD) { return 1ll * a * b % p; }
template<typename T> T cadd(T &a, T b, T p = MOD) { return a = add(a, b, p); }
template<typename T> T cdel(T &a, T b, T p = MOD) { return a = del(a, b, p); }
template<typename T> T cmul(T &a, T b, T p = MOD) { return a = mul(a, b, p); }
template<typename T> bool cmax(T &a, T b) { return a < b ? a = b, true : false; }
template<typename T> bool cmin(T &a, T b) { return a > b ? a = b, true : false; }

namespace FastIO {
	constexpr int LEN = 1 << 20;
	char in[LEN + 1], out[LEN + 1];
	char *pin = in, *pout = out, *ein = in, *eout = out + LEN;

	char gc() { return pin == ein && (ein = (pin = in) + fread(in, 1, LEN, stdin), ein == in) ? EOF : *pin ++; }
	void pc(char c) { pout == eout && (fwrite(out, 1, LEN, stdout), pout = out); (*pout ++) = c; return; }
	void Flush() { fwrite(out, 1, pout - out, stdout); pout = out; }

	template<typename T> T Read() {
		T x = 0; int f = 1; char ch = gc();
		while (ch < '0' || ch > '9') f = (ch == '-' ? (~f + 1) : f), ch = gc();
		while (ch >= '0' && ch <= '9') x = (x << 1) + (x << 3) + (ch ^ 48), ch = gc();
		return x * f;
	}
	template<typename T> void Write(T x, char c) {
		static char stk[40]; int tp = 0;
		if (x < 0) pc('-'), x = ~x + 1;
		do stk[tp++] = x % 10 + 48, x /= 10; while (x);
		while (tp --) pc(stk[tp]); pc(c); return;
	}
	void Read(char *s) {
		char ch = gc();
		while (!((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') ||
			(ch >= '0' && ch <= '9'))) ch = gc();
		while ((ch != EOF) && ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') ||
			(ch >= '0' && ch <= '9'))) *s = ch, s ++, ch = gc();
		*s = '\0'; return;
	}
	void Write(char *s) {
		while (*s != '\0') pc(*s), s ++; return;
	}
	void Puts(char *s) {
		Write(s), pc('\n'); return;
	}
}

#define getchar FastIO::gc
#define putchar FastIO::pc
#define Flush FastIO::Flush
#define Read FastIO::Read
#define Write FastIO::Write
#define Puts FastIO::Puts

constexpr int N = 2e6 + 5;
int len, n, m, a[N], sm1[N], sm0[N], ans[N];
char s[N];

bool check(int n, int m, int i) {
	int l = 1, r = i, ans = -1, cnt = m - n + 1;
	while (l <= r) {
		int mid = l + r >> 1;
		if (sm1[i] - sm1[mid - 1] >= cnt)
			ans = mid, l = mid + 1;
		else r = mid - 1;
	}
	if (!~ans) return false;
	return sm0[i] - sm0[ans - 1] <= n - 1;
}

void slv() {
	scanf("%d%d", &n, &m), scanf("%s", s + 1);
	if (n > m) swap(n, m); len = n + m;
	for (int i = 1; i <= len; i ++)
		a[i] = s[len - i + 1] - '0',
		sm0[i] = !a[i] + sm0[i - 1],
	sm1[i] = a[i] + sm1[i - 1];
	for (int i = len, x = n, y = m; i >= 1; i --) {
		if (x > y) swap(x, y);
		if (!x) ans[y --] += a[i];
		else if (!a[i]) x --;
		else {
			if (check(x, y, i - 1)) ans[x --] ++;
			else ans[y --] ++;
		}
	}
	len ++;
	for (int i = 1; i <= len; i ++)
		if (ans[i] > 1) ans[i + 1] += ans[i] >> 1, ans[i] &= 1;
	while (!ans[len] && len > 1) len --;
	while (len) putchar(ans[len] + '0'), len --;
	Puts(""); return;
}
void clr() {
	for (int i = 0; i <= n + m + 2; i ++)
		a[i] = sm0[i] = sm1[i] = ans[i] = 0;
	return;
}

bool Med;
int main() {
#ifdef LOCAL
	fprintf(stderr, "%.3lf Mb\n", fabs((&Mbe - &Med) / 1048576.0));
#endif
//	int T = 1;
	int T; scanf("%d", &T);
	while (T --) slv(), clr();
	Flush();
#ifdef LOCAL
	fprintf(stderr, "%d ms\n", (int)clock());
#endif
	return 0;
}