Transmission (JA3-Task-4-Message) C++

#include <iostream>
#include <string>
#include <sstream>
#include <map>
#include <vector>
#include <algorithm>

using namespace std;

void parse(const string& str, vector<vector<string>>& vResult)
{
    map<string, int> mList;
    stringstream ss(str);
    string token;
    char delim = ' ';
    while (getline(ss, token, delim) && token[0] != '.')
        mList[token]++;

    using pair_type = decltype(mList)::value_type;
    int nMaxCount = max_element(mList.begin(), mList.end(),
        [](const pair_type& p1, const pair_type& p2)
        { return p1.second < p2.second; })->second;
    vResult.resize(nMaxCount + 1);
    for (const pair_type& item : mList)
        vResult[item.second].push_back(item.first);
}

int main()
{
    cin.sync_with_stdio(false);
    cout.sync_with_stdio(false);

    string szInput;
    getline(cin, szInput, '\n');

    vector<vector<string>> vResult;
    parse(szInput, vResult);

    size_t nQueries;
    cin >> nQueries;

    for (size_t i = 0; i < nQueries; ++i)
    {
        size_t nIndex, nCount;
        cin >> nIndex >> nCount;
        if (nIndex < vResult.size() && nCount < vResult[nIndex].size())
            cout << vResult[nIndex][nCount] << '\n';
        else
            cout << '.' << '\n';
    }

    return 0;
}