Re: Lisp problem to solve

John Thingstad wrote:

Pn++ Tue, 20 Nov 2007 23:59:24 +0100, skrev Mark Tarver
<dr.mtarver@ukonline.co.uk>:
 

On 20 Nov, 14:48, ryan.dufra...@gmail.com wrote:

You are given a list of transactions along with the
profits from the transactions. Write code that will return the
transaction with the maximum profit. If many transactions have the
same and maximusm profit, the code can return any of these. For
example,
given ((T1 20) (T2 88) (T3 188) (T4 99) (T5 66)), the code should.
return T3.
>
I am looking for code or pseudocode.

>
(SETQ *LIST* '((T1 20) (T2 88) (T3 188) (T4 99) (T5 66)))
>
Shortest solution is 1 line.
>
(FIRST (FIRST (SORT *LIST* (FUNCTION (LAMBDA (X Y) (> (SECOND X)
(SECOND Y)))))))
>
Mark
>

 
or (caar (sort *list* #'> :key #'second))

Gauche Scheme:

(define List '((T1 20) (T2 88) (T3 188) (T4 99) (T5 66)))

(caar (sort List > last))
  ===>
T3

Without sorting:

(car
  (reduce
    (lambda(b a) (if (> (last b) (last a)) b a))
    #f
    List))


Reverse look-up in association list:

(car
  (let ((biggest (apply max (map last List))))
    (rassoc (list biggest) List)))