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.*;
  import java.util.Random;
  
  public class B {
      static final Reader sc = new Reader();
  
      public static void main(String[] args) throws IOException {
          int t = sc.nextInt();
          while (t-- > 0) {
              //Solve here
              int n = sc.nextInt();
              int[] ar = new int[n];
              int zero=0,one=0;
              for (int i = 0; i < n; i++) {
                  ar[i] = sc.nextInt();
                  if (ar[i]==0) zero++;
                  if (ar[i]==1) one++;
              }
              long sum=(long) Math.pow(2,zero)*one;
              System.out.println(sum);
          }
      }
  
  
  
  
      static int[] arrayIn(int n) throws IOException {
          int arr[] = new int[n];
          for (int i = 0; i < n; i++) {
              arr[i] = sc.nextInt();
          }
          return arr;
      }
  
  
      static class Reader {
          final private int BUFFER_SIZE = 1 << 16;
          private DataInputStream din;
          private byte[] buffer;
          private int bufferPointer, bytesRead;
  
          public Reader() {
              din = new DataInputStream(System.in);
              buffer = new byte[BUFFER_SIZE];
              bufferPointer = bytesRead = 0;
          }
  
          public Reader(String file_name) throws IOException {
              din = new DataInputStream(new FileInputStream(file_name));
              buffer = new byte[BUFFER_SIZE];
              bufferPointer = bytesRead = 0;
          }
  
          public String readLine() throws IOException {
              byte[] buf = new byte[64]; // line length
              int cnt = 0, c;
              while ((c = read()) != -1) {
                  if (c == '\n')
                      break;
                  buf[cnt++] = (byte) c;
              }
              return new String(buf, 0, cnt);
          }
  
          public int nextInt() throws IOException {
              int ret = 0;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
              do {
                  ret = ret * 10 + c - '0';
              } while ((c = read()) >= '0' && c <= '9');
  
              if (neg)
                  return -ret;
              return ret;
          }
  
          public long nextLong() throws IOException {
              long ret = 0;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
              do {
                  ret = ret * 10 + c - '0';
              }
              while ((c = read()) >= '0' && c <= '9');
              if (neg)
                  return -ret;
              return ret;
          }
  
          public double nextDouble() throws IOException {
              double ret = 0, div = 1;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
  
              do {
                  ret = ret * 10 + c - '0';
              }
              while ((c = read()) >= '0' && c <= '9');
  
              if (c == '.') {
                  while ((c = read()) >= '0' && c <= '9') {
                      ret += (c - '0') / (div *= 10);
                  }
              }
  
              if (neg)
                  return -ret;
              return ret;
          }
  
          private void fillBuffer() throws IOException {
              bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
              if (bytesRead == -1)
                  buffer[0] = -1;
          }
  
          private byte read() throws IOException {
              if (bufferPointer == bytesRead)
                  fillBuffer();
              return buffer[bufferPointer++];
          }
  
          public void close() throws IOException {
              if (din == null)
                  return;
              din.close();
          }
      }
  
      static boolean prime[];
      static int M = 1_000_000_007;
      static final Random random = new Random();
  
  
      static long nCk(int n, int k) {
          return (modMult(fact(n), power(modMult(fact(n - k), fact(k)), M - 2)));
      }
  
      static long fact(long n) {
  
          long fact = 1;
          for (int i = 1; i <= n; i++) {
              fact = modMult(fact, i);
          }
          return fact % M;
      }
  
      static long modMult(long a, long b) {
          return a * b % M;
      }
  
      static long power(long x, long y) {
          long res = 1;
          x = x % M;
          if (x == 0)
              return 0;
          while (y > 0) {
              if ((y & 1) != 0)
                  res = (res * x) % M;
              y = y >> 1;
              x = (x * x) % M;
          }
          return res;
      }
  
      static void sieveOfEratosthenes(int n) {
          prime = new boolean[n + 1];
          for (int i = 0; i <= n; i++)
              prime[i] = true;
          prime[0] = false;
          if (1 <= n)
              prime[1] = false;
          for (int p = 2; p * p <= n; p++) {
  
              if (prime[p] == true) {
  
                  for (int i = p * p; i <= n; i += p)
                      prime[i] = false;
              }
          }
      }
  }
  