SumDividedBy7.cpp

#include <iostream>
#include <cmath>

using namespace std;
const int NUMS = 16;
int num[NUMS + 10];

inline int Bit(int n, int i) { return ( n & (1 << i)); }

int main(void) {
    int t;
    cin >> t;
    while(t--) {
        int n; 
        cin >> n;
        int totalSolutions = 0;
        for (int i = 0; i < n; ++i) {
            cin >> num[i];
        }
        int tmp = pow(2.0, n);
        for (int i = 0; i < tmp; i++) {
            int sum = 0;
            for (int k = 0; k < n; ++k) {
                if (Bit(i, k)) 
                    sum += num[k];
            }
                if (sum % 7 == 0) 
                    totalSolutions++;
        }

            cout << totalSolutions << endl;
    }
    return 0;
}