void countSort(vector< vector<string> > arr) {
    int arrSize = arr.size();
    int half = arrSize/2;
    for(int i=0; i<half; i++) {
        arr[i][1] = "-";
    }
    vector< vector<string> > result(100);
     for (int j = 0; j < arrSize; j++) {
        int idx = stoi(arr[j][0]);
        string res = arr[j][1];

        result[idx].push_back(res);
    }
    for (size_t i=0; i<result.size(); i++) {
        vector<string> sub = result[i];
        for (size_t j=0; j<sub.size(); j++) {
            cout << result[i][j] << " " ;
        }
    }
}