I understand that just to set up an environment for CP, it's not needed. But it's a fact that it is one of the best piece of software out there and it's sophistication makes you learn how great softwares are built. I use Doom Emacs for this, you can add the below snippet in config.el, then compile and run your code by SPC-e-c

(map! :leader
      (:prefix ("e" . "execute")
        :desc "C/C++"
        "c" #'compileandrun))

(defun compileandrun()
  (interactive)
  (let* ((src (file-name-nondirectory (buffer-file-name)))
         (exe (file-name-sans-extension src)))
    (compile (concat "g++ " src " -o " exe " && timeout 1s ./" exe ))))

How does Codeforces deals with malicious code. Does it handle this on code level like blacklisting or at OS level?