CountNonDivisible

// you can use includes, for example:
#include <algorithm>

// you can write to stdout for debugging purposes, e.g.
// cout << "this is a debug message" << endl;

vector<int> solution(vector<int> &A) {
    // write your code in C++14 (g++ 6.2.0)
    size_t N = A.size();
    auto max = *std::max_element(A.begin(), A.end()) + 1;
    
    // Calculate occurences of each number in the array
    vector<int> counts(max, 0);
    for (size_t i = 0; i < N; ++i) {
        counts[A[i]]++;
    }
    
    vector<int> result(N, 0);
    for (size_t i = 0; i < N; ++i) {
        // Calulate how many of its divisors are in the array
        int divisors = 0;
        // Find all divisors for A[i] element 
        for (int j = 1; j * j <= A[i]; ++j) {
            if (A[i] % j == 0) {
                divisors += counts[j];
                
                // Check reverse divisor
                if (A[i] / j != j) {
                    divisors += counts[A[i] / j];
                }
            }
        }
        // Subtract the number of divisors from the number of elements in the array
        result[i] = N - divisors;
    }
    
    return result;
}