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: #include <bits/stdc++.h>
  using namespace std;
  long long int spf[100001];
  long long int dx[4] = {-1, 0, 1, 0};
  long long int dy[4] = {0, 1, 0, -1};
  bool isPrime(long long int n) {
    if (n <= 1) return false;
    if (n <= 3) return true;
    if (n % 2 == 0 || n % 3 == 0) return false;
    for (long long int i = 5; i * i <= n; i = i + 6)
      if (n % i == 0 || n % (i + 2) == 0) return false;
    return true;
  }
  long long int mod = 1e9 + 7;
  long long int power(long long int x, long long int y, long long int p) {
    long long int res = 1;
    x = x % p;
    while (y > 0) {
      if (y & 1) res = (res * x) % p;
      y = y >> 1;
      x = (x * x) % p;
    }
    return res;
  }
  long long int modInverse(long long int n, long long int p) {
    return power(n, p - 2, p);
  }
  long long int nCrModPFermat(long long int n, long long int r, long long int p) {
    if (n < r) return 0;
    if (r == 0) return 1;
    long long int fac[n + 1];
    fac[0] = 1;
    for (long long int i = 1; i <= n; i++) fac[i] = (fac[i - 1] * i) % p;
    return (fac[n] * modInverse(fac[r], p) % p * modInverse(fac[n - r], p) % p) %
           p;
  }
  void sieve() {
    spf[1] = 1;
    for (long long int i = 2; i < 100001; i++) spf[i] = i;
    for (long long int i = 4; i < 100001; i += 2) spf[i] = 2;
    for (long long int i = 3; i * i < 100001; i++) {
      if (spf[i] == i) {
        for (long long int j = i * i; j < 100001; j += i)
          if (spf[j] == j) spf[j] = i;
      }
    }
  }
  vector<long long int> getFactorization(long long int x) {
    vector<long long int> ret;
    while (x != 1) {
      if (ret.size() == 0)
        ret.push_back(spf[x]);
      else if (ret.back() != spf[x]) {
        ret.push_back(spf[x]);
      }
      x = x / spf[x];
    }
    return ret;
  }
  long long int bs1(long long int a[], long long int n, long long int x) {
    long long int l = -1, r = n;
    long long int pos = 0;
    while (l + 1 < r) {
      long long int m = (l + r) / 2;
      if (a[m] >= x) {
        r = m;
      } else {
        l = m;
      }
    }
    return r + 1;
  }
  long long int bs2(long long int a[], long long int n, long long int x) {
    long long int l = -1, r = n;
    long long int pos = 0;
    while (l + 1 < r) {
      long long int m = (l + r) / 2;
      if (a[m] > x) {
        r = m;
      } else {
        l = m;
      }
    }
    return l + 1;
  }
  long long int powr(long long int a, long long int b) {
    long long int x = 1;
    while (b--) {
      x = x * a;
    }
    return x;
  }
  struct cpp {
    long long int x, y;
  };
  bool comp(struct cpp a, struct cpp b) { return a.x < b.x; }
  signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    long long int t = 1;
    cin >> t;
    long long int mod = 1e9 + 7;
    while (t--) {
      long long int n, m, i, j, k, ct0 = 0, ct1 = 0;
      cin >> n;
      long long int a[n];
      for (i = 0; i < n; i++) {
        cin >> a[i];
        if (a[i] == 0) {
          ct0++;
        }
        if (a[i] == 1) {
          ct1++;
        }
      }
      if (ct1 == 0) {
        cout << 0 << endl;
        continue;
      } else if (ct0 == 0) {
        cout << ct1 << endl;
        continue;
      } else {
        long long int ans = 1;
        for (j = 0; j < ct0; j++) {
          ans *= 2;
        }
        cout << ans * ct1 << endl;
        continue;
      }
    }
  }
  