src/problems/fibd.lisp @ 97dda08645b3
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author |
Steve Losh <steve@stevelosh.com> |
date |
Mon, 08 Aug 2022 19:26:18 -0400 |
parents |
2735aa6aab79 |
children |
(none) |
(defpackage :rosalind/fibd (:use :cl :rosalind :losh :iterate))
(in-package :rosalind/fibd)
(define-problem fibd (data stream)
"6 3"
"4"
(iterate
(with months = (read data))
(with lifespan = (read data))
(for month :from 2 :to months)
(labels ((ref (array index)
(if (plusp index)
(aref array index)
0))
(breeding (month)
(- (ref population (- month 1))
(deaths month)))
(births (month)
(breeding (- month 1)))
(deaths (month)
(ref births (- month lifespan)))
(population (month)
(+ (breeding month)
(births month))))
;; We initialize the buffers with NIL in index 0 for the 1-based months,
;; and 1 in index 0 for the initial pair of rabbits.
(u:buffering (u:returning-final (population month))
:into population
:initial-contents '(nil 1))
(u:buffering (births month)
:into births
:initial-contents '(nil 1)))))
#; Scratch --------------------------------------------------------------------
(problem-fibd "45 6")
;; (solve fibd)