Check out the solution here.
import java.io.*; import java.util.*; import java.util.Arrays; public class MochaandMath { public static void main(String[] args) { FastScanner sc = new FastScanner(); PrintWriter pw = new PrintWriter(System.out); int i,x; int T = sc.ni(); for (int t = 0; t < T; t++) { int n = sc.ni(); int arr[]=new int[n]; for(i=0;i<n;i++) { arr[i]=sc.ni(); } x=arr[0]; for(i=1;i<n;i++) x&=arr[i]; pw.println(x); }
pw.close();
}
static class FastScanner {
BufferedReader br;
StringTokenizer st;
public FastScanner() {
br = new BufferedReader(new InputStreamReader(System.in));
}
String next() {
while (st == null || !st.hasMoreElements()) {
try {
st = new StringTokenizer(br.readLine());
} catch (IOException e) {
e.printStackTrace();
}
}
return st.nextToken();
}
int ni() {
return Integer.parseInt(next());
}
}}



