Euler_16.cpp

#include <numeric>

#include "Euler.h"

int Euler::DigitSum()
{
    std::vector<int> digits;

    digits.push_back(2);

    for (int i = 1; i < 1000; ++i)
    {
        for (unsigned j = 0; j < digits.size(); ++j)
            digits[j] *=2;

        for (unsigned j = 0; j < digits.size(); ++j)
        {
            if (digits[j] >= 10)
            {
                digits[j] = digits[j] % 10;

                if (j == digits.size() - 1)
                {
                    digits.push_back(1);
                }
                else
                {
                    digits[j + 1] += 1;
                }
            }
        }
    }

    return std::accumulate(digits.begin(), digits.end(), 0);
}