A>struct pivot_entry
A>{
A>    uint32_t nCnt;
A>    double fSum;
A>    double fPart;
A>};
A>using pivot_key = std::tuple<std::wstring, std::wstring, std::wstring, std::wstring>;
A>using pivot_map = std::unordered_map<pivot_key, pivot_entry>;
A>

using pivot_map_key = std::tuple<std::wstring, std::wstring, std::wstring, std::wstring>;

struct pivot_map_hash
{
    size_t operator()(const pivot_map_key& key) const
    {
        using str_hash = std::hash<std::wstring>;
        return
            str_hash()(std::get<0>(key)) ^
            (str_hash()(std::get<1>(key)) << 1) ^
            (str_hash()(std::get<2>(key)) << 2) ^
            (str_hash()(std::get<3>(key)) << 3);
    }
};

using pivot_map = std::unordered_map<pivot_map_key, pivot_entry, pivot_map_hash>;