#include <benchmark/benchmark.h>
#include <numeric>
#include <random>

constexpr unsigned mcd1(unsigned a, unsigned b)
{
    while (a != b)
        if (a > b)
            a -= b;
        else
            b -= a;
    return a;
}

constexpr unsigned mcd2(unsigned a, unsigned b)
{
    if (b == 0)
        return a;
    else
        return mcd2(b, a % b);
}

static_assert(mcd1(48, 60) == mcd2(48, 60), "mcd1(48, 60) != mcd2(48, 60)!!!");

template<auto f> static void test(benchmark::State &state)
{
    std::mt19937_64 generator(0);
    std::uniform_int_distribution<unsigned> distribution;
    auto rng = [&]() { return distribution(generator); };
    for (auto _: state)
        benchmark::DoNotOptimize(f(rng(), rng()));
}

BENCHMARK(test<mcd1>)->Iterations(1'000'000);
BENCHMARK(test<mcd2>)->Iterations(1'000'000);

BENCHMARK_MAIN();