#include <algorithm>
#include <cassert>
#include <cstddef>
#include <iterator>
#include <random>

const std::size_t N = 1'000'000;
const auto seed = std::random_device{}();

std::default_random_engine rng;

int f1()
{
    int result = 0;
    rng.seed(seed);
    for (std::size_t i = 0; i < N; ++i)
        if (rng() % 2 == 0)
            result += rng();
        else
            result -= rng();
    return result;
}

int f2()
{
    int result = 0;
    rng.seed(seed);
    for (std::size_t i = 0; i < N; ++i)
        switch (rng() % 2)
        {
            case 0: result += rng(); break;
            case 1: result -= rng(); break;
        }
    return result;
}

int main(int argc, char *argv[])
{
    assert(f1() == f2());
}