;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/survivor.el

(require 'cl-lib)

(defun cost-at-day (day)
  (apply #'+ (number-sequence 1 day)) )
;; (cost-at-day 5) ; 15
;; (cost-at-day 1) ;  1
;; (cost-at-day 0) ;  0

;; compute difficulty
(defun compare-difficulty ()
  (let*((au (cost-at-day 48)) ; 1176
        (us (cost-at-day 39)) ;  780
        (se (cost-at-day 28)) ;  406
        (au-vs-us (* (/ au (* us 1.0)) 100))
        (us-vs-se (* (/ us (* se 1.0)) 100))
        (au-vs-se (* (/ au (* se 1.0)) 100))
        (au-vs-us-str (format "\n;; Australia - USA    %.0f%%\n" au-vs-us))
        (us-vs-se-str (format   ";; USA       - Sweden %.0f%%\n" us-vs-se))
        (au-vs-se-str (format   ";; Australia - Sweden %.0f%%\n" au-vs-se)) )
    (insert au-vs-us-str)
    (insert us-vs-se-str)
    (insert au-vs-se-str) ))

;; (compare-difficulty)
;; Australia - USA    151%
;; USA       - Sweden 192%
;; Australia - Sweden 290%