Polynomial Multiplication 1 Solution:

#include <bits/stdc++.h>
using namespace std;

int main(){
    // #ifndef TESTING
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    // #endif

    int cases;
    cin >> cases;
    while(cases--){
        int deg1, deg2;
        cin >> deg1;
        int poly1[deg1 + 1];
        for(int &i: poly1){
            cin >> i;
        }
        cin >> deg2;
        int poly2[deg2 + 1];
        for(int &i: poly2){
            cin >> i;
        }
        int result[deg1 + deg2 + 1] = {};
        int l1terminate = deg1 + 1;
        int l2terminate = deg2 + 1;
        for(int i = 0; i < l1terminate; i++){
            for(int j = 0; j < l2terminate; j++){
                result[i + j] += poly1[i] * poly2[j];
            }
        }
        cout << deg1 + deg2 << endl;
        for(int i: result){
            cout << i << " ";
        }
        cout << endl;
    }

    return 0;   
}