第8回オフラインリアルタイムどう書くの問題の回答例。C++で。

周回遅れ再び。
大力技。

お題はこちら http://qiita.com/items/709d61dff282cff7a890

# include <iostream>
# include <sstream>
# include <iomanip>
# include <string>
# include <vector>
# include <utility>

typedef std::pair<int, int> Pos;
typedef std::vector<Pos>    Positions;

std::string solve(const std::string& input)
{
    std::istringstream iss(input);
    unsigned long wall;
    unsigned long bomb;
    char          delimiter;
    iss >> std::hex >> wall >> delimiter >> bomb;

    int       field[5][6];
    Positions bombs;
    for(int i = 0; i < 30; ++i)
    {
        field[i / 6][i % 6] = (wall >> (31 - i)) & 1;
        if(((bomb >> (31 - i)) & 1) != 0)
        {
            bombs.push_back(std::make_pair(i / 6, i % 6));
        }
    }

    for(Positions::iterator i = bombs.begin(); i != bombs.end(); ++i)
    {
        field[i->first][i->second] = 2;

        for(int d = 1; d < 5; ++d)
        {
            int row = i->first + d;
            int col = i->second;
            if((row >= 5) || (field[row][col] == 1))
            {
                break;
            }
            else
            {
                field[row][col] = 2;
            }
        }

        for(int d = 1; d < 5; ++d)
        {
            int row = i->first - d;
            int col = i->second;
            if((row < 0) || (field[row][col] == 1))
            {
                break;
            }
            else
            {
                field[row][col] = 2;
            }
        }

        for(int d = 1; d < 6; ++d)
        {
            int row = i->first;
            int col = i->second + d;
            if((col >= 6) || (field[row][col] == 1))
            {
                break;
            }
            else
            {
                field[row][col] = 2;
            }
        }

        for(int d = 1; d < 6; ++d)
        {
            int row = i->first;
            int col = i->second - d;
            if((col < 0) || (field[row][col] == 1))
            {
                break;
            }
            else
            {
                field[row][col] = 2;
            }
        }
    }

    unsigned long result = 0;

    for(int i = 0; i < 30; ++i)
    {
        result <<= 1;
        result |= (field[i / 6][i % 6] == 2 ? 1 : 0);
    }
    result <<= 2;

    std::ostringstream oss;
    oss.fill('0');
    oss << std::hex << std::setw(8) << result;

    return oss.str();
}

void test(const std::string& input, const std::string& expected)
{
    std::string actual = solve(input);
    std::cout
        << "expected: " << expected
        << " / actual: " << actual
        << " => " << (actual == expected ? "o" : "x") << "\n";
}

int main(int, char* [])
{
    /*0*/ test( "802b1200/01400c20", "53c40cfc" );
    /*1*/ test( "28301068/84080504", "d64fef94" );
    /*2*/ test( "100a4010/80010004", "e241850c" );
    /*3*/ test( "81020400/000000fc", "0e3cfbfc" );
    /*4*/ test( "80225020/7e082080", "7fdd24d0" );
    /*5*/ test( "01201200/40102008", "fe1861fc" );
    /*6*/ test( "00201000/01000200", "43c48f08" );
    /*7*/ test( "00891220/81020408", "ff060c1c" );
    /*8*/ test( "410033c0/0c300000", "3cf0c000" );
    /*9*/ test( "00000000/01400a00", "7bf7bf78" );
    /*10*/ test( "00000000/20000a00", "fca2bf28" );
    /*11*/ test( "00000000/00000000", "00000000" );
    /*12*/ test( "00cafe00/00000000", "00000000" );
    /*13*/ test( "aaabaaaa/50000000", "51441040" );
    /*14*/ test( "a95a95a8/56a56a54", "56a56a54" );
    /*15*/ test( "104fc820/80201010", "ea30345c" );
    /*16*/ test( "4a940214/05000008", "05000008" );
    /*17*/ test( "00908000/05000200", "ff043f48" );
    /*18*/ test( "00c48c00/fe1861fc", "ff3873fc" );
    /*19*/ test( "00000004/81020400", "fffffff0" );
    /*20*/ test( "111028b0/40021100", "e08fd744" );
    /*21*/ test( "6808490c/01959000", "17f7b650" );
    /*22*/ test( "30821004/81014040", "c75de5f8" );
    /*23*/ test( "0004c810/10003100", "fe4937c4" );
    /*24*/ test( "12022020/88200000", "edf08208" );
    /*25*/ test( "2aa92098/01160000", "45165964" );
    /*26*/ test( "00242940/10010004", "fc43c43c" );
    /*27*/ test( "483c2120/11004c00", "33c3de10" );
    /*28*/ test( "10140140/44004a04", "eda3fe3c" );
    /*29*/ test( "0c901d38/72602200", "f36da280" );

    return 0;
}