第五回オフラインリアルタイムどう書くの解答(C++)

#define BOOST_TEST_MAIN
#include <boost/test/included/unit_test.hpp>

namespace
{
typedef std::map<std::string, std::string> m_t;
typedef m_t::iterator it_t;
const std::string Jo = "o";

std::string get_hand(const std::string& s, const bool hand)
{
    std::string::const_iterator it = std::find(s.begin(), s.end(), ',');
    return hand ? std::string(++it, s.end()) : std::string(s.begin(), it);
}

bool stronger(const std::string& h, const std::string& f)
{
    const std::string ranks = "3456789TJQKA2o";
    return ranks.find(f) < ranks.find(h);
}

std::string get_field_rank(const std::string& s)
{
    std::string field_rank = s.substr(1,1);
    if(field_rank == Jo)
    {
        if(s.length() == 2)
        {
            return Jo;
        }
        field_rank = s.substr(3,1);
    }
    return field_rank;
}

m_t get_usable_hand(const std::string& h, const std::string& f)
{
    m_t m;
    std::string field_rank = get_field_rank(f);
    if(field_rank == Jo)
    {
        return m;
    }
    for(size_t i=1; i<h.length(); i+=2)
    {
        std::string hand_rank = h.substr(i,1);
        if(stronger(hand_rank, field_rank))
        {
            m[hand_rank] += h.substr(i-1,2);
        }
    }
    const size_t num_of_field_cards =
            m[Jo].empty() ? f.length()/2 : f.length()/2-1;
    for(m_t::const_iterator it = m.begin(); it != m.end(); ++it)
    {
        if(it->second.length()/2 < num_of_field_cards && it->first != Jo)
        {
            m.erase(it->first);
        }
    }
    return m;
}

void depth_first_search(
        int d, int i, const std::string& h, const size_t n,
        const std::string& str, std::set<std::string>& s)
{
    if(d == i)
    {
        if(str.length() == n)
        {
            s.insert(str);
        }
        return;
    }
    depth_first_search(d, i+2, h, n, str, s);
    depth_first_search(d, i+2, h, n, str + h.substr(i, 2), s);
}

std::string solve_impl(const std::string& h, const std::string& f)
{
    std::set<std::string> s;
    depth_first_search(h.length(), 0, h, f.length(), "", s);
    std::string ret = "";
    for(std::set<std::string>::iterator it = s.begin(); it != s.end(); ++it)
    {
        ret += *it + ",";
    }
    return ret;
}

std::string solve(const std::string& s)
{
    std::string hand = get_hand(s,true);
    if(hand.empty())
    {
        return "-";
    }
    std::string field = get_hand(s,false);
    m_t m = get_usable_hand(hand,field);
    std::string ret = "";
    for(it_t it = m.begin(); it != m.end(); ++it)
    {
        if(!m[Jo].empty() && 4 <= field.length() && it->first != Jo)
        {
            it->second += m[Jo];
        }
        ret += solve_impl(it->second, field);
    }
    return ret.empty() ? "-" : ret.substr(0,ret.length()-1);
}
}

BOOST_AUTO_TEST_CASE( solve_test1 )
{
    BOOST_CHECK_EQUAL(solve("DJ,"), "-");
}