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.*;
  
  public class B_Luntik_and_Subsequences {
  
      static final int MOD = (int) 1e9 + 7;
      static final int INT_POSITIVE_INFINITY = Integer.MAX_VALUE;
      static final long LONG_POSITIVE_INFINITY = Long.MAX_VALUE;
      static final int INT_NEGATIVE_INFINITY = Integer.MIN_VALUE;
      static final long LONG_NEGATIVE_INFINITY = Long.MIN_VALUE;
      static StringBuilder result = new StringBuilder();
  
      static class Pair {
          int a;
          int b;
  
          public Pair(int a, int b) {
              this.a = a;
              this.b = b;
          }
      }
  
      public static void main(String args[]) throws IOException {
          FastReader fr = new FastReader();
  
          int tc = fr.nextInt();
          while (tc-- > 0) {
              int n = fr.nextInt();
  
              int zeroes = 0;
              int ones = 0;
              for (int i = 1; i <= n; i++) {
                  int input = fr.nextInt();
                  if (input == 0) {
                      zeroes++;
                  } else if (input == 1) {
                      ones++;
                  }
              }
  
              long a = 1L << zeroes;
              result.append((a * ones) + "\n");
          }
  
          System.out.print(result);
      }
  
      static class FastReader {
          InputStreamReader ir;
          BufferedReader br;
          StringTokenizer st;
  
          public FastReader() {
              ir = new InputStreamReader(System.in);
              br = new BufferedReader(ir);
          }
  
          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;
          }
      }
  
      static int fastPow(long b, long e) {
          long curr = b;
          long res = 1;
  
          while (e != 0) {
              if ((e & 1) != 0) {
                  res = (res * curr);
              }
              curr = (curr * curr);
              e >>= 1;
          }
  
          return (int) res;
      }
  
      static int gcd(int a, int b) {
          if (b > a) {
              return gcd(b, a);
          }
  
          if (b == 0) {
              return a;
          }
  
          return gcd(b, a % b);
      }
  }