C++で初Bitsの出

最近C++成分が足りないので.

ここで問題。0 の三連続、[0,0,0] が最初に現れる位置は、平均で何ビット目でしょう？

初Bitsの出 -- d.y.d.

#include <iostream>
#include <vector>
#include <typeinfo>
#include <ctime>
#include <boost/range.hpp>
#include <boost/range/adaptors.hpp>
#include <boost/range/algorithm.hpp>
#include <boost/assign.hpp>
#include <boost/random.hpp>

using std::cout;
using std::endl;
using namespace boost::assign;

namespace {
	boost::mt19937 gen(static_cast<unsigned long>(time(0)));
}

template<typename RandomAccessRange>
std::size_t first_occurence(RandomAccessRange const & rng) {
	using namespace boost;
	namespace range = boost::range;
	namespace adp = boost::adaptors;

	uniform_smallint<> dst(0, 1);
	variate_generator<
		mt19937&, uniform_smallint<>
	> rand(::gen, dst);

	std::vector<int> xs;
	while (size(xs) < size(rng)
		|| ((xs | adp::sliced(size(xs)-size(rng), size(xs))) != rng))
	{
		xs += rand();
		//xs += std::rand() % 2;
	}
}

namespace {
	static size_t const TEST_COUNT = 10000;
}

void test (std::vector<int> const & xs) {
	unsigned int sum=0;
	for (size_t i=0; i<TEST_COUNT; ++i)
		sum += first_occurence(xs);
	cout << sum << " / " << static_cast<double>(sum)/TEST_COUNT << endl;
}

int main (void) {
{
	std::vector<int> const xs = list_of(0)(0)(0);
	test(xs);
}
{
	std::vector<int> const xs = list_of(0)(0)(1);
	test(xs);
}
}

randomメンドクサイなー