Count Pairs With a Sum

#include <iostream>
#include <vector>
#include <string>
#include <stdexcept>

long long count_pairs_with_sum(std::vector<long long> numbers, long long target) {
    long long count = 0;
    for (int i = 0; i < numbers.size(); i++) {
        for (int j = i+1; j < numbers.size(); j++) {
            if (i != j && numbers[i] + numbers[j] == target) {
                count++;
            }
        }
    }

    return count;
}

int main() {
    // Try your function with the first example. Change the input to test other cases.
    auto result = count_pairs_with_sum(std::vector<long long>{1, 5, 3, 3, 4}, 6);
    std::cout << result << std::endl;
    return 0;
}