#include <generator>
#include <algorithm>
#include <chrono>
#include <print>

constexpr int N = 100000;

std::generator<int> f() {
  co_yield 1;
}

std::generator<int> g_rvalue()
{
  for (int i = 0; i < N; i++) {
    auto f1 = f();
    co_yield std::ranges::elements_of(std::move(f1));
  }
}

std::generator<int> g_lvalue()
{
  for (int i = 0; i < N; i++) {
    auto f1 = f();
    co_yield std::ranges::elements_of(f1);
  }
}

int main()
{
  {
    auto start = std::chrono::high_resolution_clock::now();
    int res = std::ranges::fold_left(g_rvalue(), 0, std::plus<int>());
    auto duration = std::chrono::high_resolution_clock::now() - start;
    std::println("With elements_of(rvalue generator)\nresult: {}, time: {}, per element: {}", res, std::chrono::duration_cast<std::chrono::microseconds>(duration), duration / N);
  }

  {
    auto start = std::chrono::high_resolution_clock::now();
    int res = std::ranges::fold_left(g_lvalue(), 0, std::plus<int>());
    auto duration = std::chrono::high_resolution_clock::now() - start;
    std::println("With elements_of(lvalue generator)\nresult: {}, time: {}, per element: {}", res, std::chrono::duration_cast<std::chrono::microseconds>(duration), duration / N);
  }
}