description: Luntik came out for a morning stroll and found an array a of length n. He calculated the sum s of the elements of the array (s= ∑_{i=1}^{n} a_i). Luntik calls a subsequence of the array a nearly full if the sum of the numbers in that subsequence is equal to s-1.
  
  Luntik really wants to know the number of nearly full subsequences of the array a. But he needs to come home so he asks you to solve that problem!
  
  A sequence x is a subsequence of a sequence y if x can be obtained from y by deletion of several (possibly, zero or all) elements.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases. The next 2 ⋅ t lines contain descriptions of test cases. The description of each test case consists of two lines.
  
  The first line of each test case contains a single integer n (1 ≤ n ≤ 60) — the length of the array.
  
  The second line contains n integers a_1, a_2, …, a_n (0 ≤ a_i ≤ 10^9) — the elements of the array a.
  
  Output
  
  For each test case print the number of nearly full subsequences of the array.
  
  Example
  
  Input
  
  
  5
  5
  1 2 3 4 5
  2
  1000 1000
  2
  1 0
  5
  3 0 2 1 1
  5
  2 1 0 3 0
  
  
  Output
  
  
  1
  0
  2
  4
  4
  
  Note
  
  In the first test case, s=1+2+3+4+5=15, only (2,3,4,5) is a nearly full subsequence among all subsequences, the sum in it is equal to 2+3+4+5=14=15-1.
  
  In the second test case, there are no nearly full subsequences.
  
  In the third test case, s=1+0=1, the nearly full subsequences are (0) and () (the sum of an empty subsequence is 0).
solution: import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintStream;
  import java.io.PrintWriter;
  import java.time.Duration;
  import java.time.Instant;
  import java.util.ArrayList;
  import java.util.StringTokenizer;
  import static java.lang.Math.min;
  import static java.lang.Math.max;
  import static java.lang.Math.abs;
  
  @SuppressWarnings("unused")
  public class Main {
  	static boolean DEBUG = false;
  
  	public static void main(String[] args) throws IOException {
  		Instant start = Instant.now();
  		if (args.length == 2) {
  			System.setIn(new FileInputStream(new File("D://program//javaCPEclipse//MyJava//src//MyJava//input.txt")));
  			// System.setOut(new PrintStream(new File("output.txt")));
  			System.setErr(new PrintStream(new File("D://program//javaCPEclipse//MyJava//src//MyJava//error.txt")));
  			DEBUG = true;
  		}
  		Reader fs = new Reader();
  		PrintWriter pw = new PrintWriter(System.out);
  		int t = fs.nextInt();
  		while (t-- > 0) {
  			int n = fs.nextInt(), a[] = fs.readArray(n);
  			int zero =0, one = 0;
  			for(int i = 0 ; i < n ; i++)
  			{
  				if(a[i] == 0) {
  					zero++;
  				}
  				else if(a[i] == 1) {
  					one++;
  				}
  			}
  			long possible_zero = (long)Math.pow(2, zero);
  			long ans = possible_zero*one;
  			pw.println(ans);
  		}
  		Instant end = Instant.now();
  		if (DEBUG) {
  			pw.println(Duration.between(start, end));
  		}
  		pw.close();
  	}
  
  	public static void print(long a, long b, long c, PrintWriter pw) {
  		pw.println(a + " " + b + " " + c);
  		return;
  	}
  
  	static class Reader {
  		BufferedReader br;
  		StringTokenizer st;
  
  		public Reader() {
  			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 nextInt() {
  			return Integer.parseInt(next());
  		}
  
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  
  		double nextDouble() {
  			return Double.parseDouble(next());
  		}
  
  		String nextLine() {
  			String str = "";
  			try {
  				str = br.readLine();
  			} catch (IOException e) {
  				e.printStackTrace();
  			}
  			return str;
  		}
  
  		int[] readArray(int n) {
  			int a[] = new int[n];
  			for (int i = 0; i < n; i++)
  				a[i] = nextInt();
  			return a;
  		}
  
  		int[][] read2Array(int n, int m) {
  			int a[][] = new int[n][m];
  			for (int i = 0; i < n; i++) {
  				for (int j = 0; j < m; j++) {
  					a[i][j] = nextInt();
  				}
  			}
  			return a;
  		}
  	}
  }