求助，样例能过

#include <bits/stdc++.h>
using namespace std;
int t, n, a, sxor;//sxor用来存前i次a的异或
unsigned long long cnt;
void print2( int n ) {//输出二进制数
	short b[32] = {0};
	int i = 0;
	for ( ; i < 32; i++ ) {
		b[i] = n % 2;
		n = n / 2;
		if ( n == 0 )break;
	}
	for ( ; i >= 0; i-- )cout<<b[i];
	cout<<"\n";
}
int main() {
	cin >> t;
	while ( t-- ) {
		cnt = sxor = 0;
		cin >> n;
		for ( int i = 1; i <= n + 1; i++ ) {
			cin >> a;
			if(i != n + 1)cnt *= 2;
			if ( a == sxor ) cnt++; //最后一次不*2
			sxor ^= a;
		}
		print2( cnt );
	}
	return 0;
}