[프로그래머스] 행렬의 곱셈 - c++

3중 for문

vector<vector<int>> solution(vector<vector<int>> arr1, vector<vector<int>> arr2) {
    vector<vector<int>> answer;
    for(int i=0;i<arr1.size();i++){
        vector<int> v;
        for(int j=0; j<arr2[0].size();j++){
            int sum=0;
            for(int k=0;k<arr1[0].size();k++){
                sum+=arr1[i][k] * arr2[k][j];
            }
            v.push_back(sum); 
        }
        answer.push_back(v);
    }
    return answer;
}```