#lang racket

;; A starting point
;; for the lottery problem...

;; lotto-help
;;  inputs: LT, a "list of tickets" and W a list of winning #s
;;  outputs: not yet determined! just for building intuition...
(define (lotto-help LT W)
  (let* (
         [P  (map (lambda (x) (first x)) LT)]
         )
    P      ;; this is the output, for now...
    ))


;; some data
(define Tix '((alice 2 4 16 33 42)  (bob 3 4 5 6 7) (cdrthecat 3 15 16 41 42) ))
(define Win '(2 3 15 32 42))

;; here, we're testing lotto-help by simply _printing_ the result
;; as currently written, this will run lotto-help and return P
;; the output should be  '(alice bob cdrthecat)
(lotto-help Tix Win)

;; to try
;; (0) run and read over the code above - WHY is it producing '(alice bob cdrthecat) ?
;; (1) change (first x) to (second x) - what will it produce?
;; (2) change (second x) to (list (first x)) - again, what will happen?
;; (3) change (list (first x)) to (list (first x) 42) - again, predict...
;; (4) change that 42 to be the *correct* score (use matches!)
;; (5) you need to sort the result! I'd suggest another line in the let*:
;;     [S    (sort L (lambda (x1 x2) (something)))]
;;     What does something have to be? You want a function that returns
;;     #t when the left-hand element should be earlier in the sorted list.
;; (6) You're nearly done! What's left?

;; Good luck!