q_runner.go

func runner(tasks []int, workers int, f func(int) int) {

	in, out := make(chan int), make(chan int)

	for i := 0; i < workers; i++ {
		go func() {
			for {
				out <- f(<-in)
			}
		}()
	}

	for _, v := range tasks {
		in <- v
	}

	var res []int

	for i := 0; i < len(tasks); i++ {
		res = append(res, <-out)
	}

	fmt.Println("Done!\n", res)
}