关于map排序问题

bool sortbyScoreDesc(const std::pair<UINT32, DT_PLAYER_DATA> &stData1, const std::pair<UINT32, DT_PLAYER_DATA> &stData2){    if (stData1.second.stPlayerRank.dwTotalScore > stData2.second.stPlayerRank.dwTotalScore)    {       return true;    }    else if(stData1.second.stPlayerRank.dwTotalScore  < stData2.second.stPlayerRank.dwTotalScore)    {        return false;    }    else    {        return (stData1.second.qwPower >= stData2.second.qwPower);    } }std::vector<std::pair<UINT32, DT_PLAYER_DATA> > vtSortRank(m_mapRankData.begin(), m_mapData.end());std::sort(vtSortRank.begin(), vtSortRank.end(), sortbyScoreDesc);