esm_doukaku_20151022.cpp

// compile:
// $ g++ -std=c++11 -o esm_doukaku_20151022 esm_doukaku_20151022.cpp

#include <iostream>
#include <sstream>
#include <string>

unsigned int char2bits(char c)
{
    unsigned int bits[] = { 0x00u, 0x80u, 0xc0u, 0xe0u, 0xf0u, 0xf8u, 0xfcu, 0xfeu, 0xffu };
    return bits[c - '0'];
}

unsigned int rotate_right(unsigned int n, int r)
{
    return ((n << (8 - r)) & 0xffu) | ((n >> r) & 0xffu);
}

std::string solve(const std::string& input)
{
    unsigned int waiting = 0;
    unsigned int eating  = 0;
    unsigned int resting = 0;

    auto i   = std::begin(input);
    auto end = std::end(input);

    while(i != end)
    {
        resting = eating;
        eating  = waiting;
        waiting = 0;
        for(int r = 0; r < 8; ++r)
        {
            auto visitors = rotate_right(char2bits(*i), r);
            if(((eating | resting) & visitors) == 0)
            {
                waiting = visitors;
                ++i;
                break;
            }
        }
    }

    auto sitting = waiting | eating | resting;

    std::ostringstream oss;
    for(int i = 0; i < 8; ++i)
    {
        oss << ((sitting >> (7 - i)) & 1u);
    }

    return oss.str();
}

void test(const std::string& input, const std::string& expected)
{
    auto actual = solve(input);
    if(actual == expected)
    {
        std::cout << '.';
    }
    else
    {
        std::cout
            << "\nFAILURE\n"
            << "input: " << input
            << ", expected: " << expected
            << ", actual: " << actual
            << std::endl;
    }
}

int main(int, char* [])
{
    test("3316", "11111110");
    test("3342153", "11111111");
    test("8", "11111111");
    test("232624", "11110110");
    test("1", "10000000");
    test("224673432", "11111000");
    test("123464334", "11111110");
    test("44372332", "11111111");
    test("2344", "11111111");
    test("6448476233", "11111100");
    test("4345174644", "11111111");
    test("77743", "11111110");
    test("2136524281", "10000000");
    test("344373", "11100000");
    test("434226", "11111111");
    test("7433223", "11111110");
    test("2246534", "11110111");
    test("634", "11111110");
    test("2222", "11111100");
    test("2442343238", "11111111");
    test("7243344", "11111111");
    test("26147234", "10111111");
    test("34424", "10011111");
    test("6334", "11011111");
    test("3828342", "11011110");
    test("4431", "11110000");
    test("2843212125", "11111111");
    test("333336482", "11000000");
    test("374", "11110000");
    test("4382333", "11100111");
    std::cout << std::endl;

    return 0;
}