Comments on: Everybody loves the Sieve of Eratosthenes http://clj-me.cgrand.net/2009/07/30/everybody-loves-the-sieve-of-eratosthenes/ When the pupil is ready to learn, a teacher will appear. Tue, 07 Sep 2010 05:36:26 +0200 http://wordpress.org/?v=2.9.2 hourly 1 By: Project Euler Problem 7 « Clojure Companion Cube http://clj-me.cgrand.net/2009/07/30/everybody-loves-the-sieve-of-eratosthenes/comment-page-1/#comment-531 Project Euler Problem 7 « Clojure Companion Cube Fri, 04 Jun 2010 08:41:58 +0000 http://clj-me.cgrand.net/2009/07/30/everybody-loves-the-sieve-of-eratosthenes/#comment-531 [...] favorite solution was by Cristophe Grande, not just because he followed a similar approach to me, but also because he was very clever in his [...] [...] favorite solution was by Cristophe Grande, not just because he followed a similar approach to me, but also because he was very clever in his [...]

]]> By: You read my blog that’s enough social interaction!! / Sieve of eratosthenes http://clj-me.cgrand.net/2009/07/30/everybody-loves-the-sieve-of-eratosthenes/comment-page-1/#comment-94 You read my blog that’s enough social interaction!! / Sieve of eratosthenes Wed, 14 Oct 2009 15:48:20 +0000 http://clj-me.cgrand.net/2009/07/30/everybody-loves-the-sieve-of-eratosthenes/#comment-94 [...] reading this post [...] [...] reading this post [...]

]]> By: zemariamm http://clj-me.cgrand.net/2009/07/30/everybody-loves-the-sieve-of-eratosthenes/comment-page-1/#comment-36 zemariamm Tue, 15 Sep 2009 02:36:14 +0000 http://clj-me.cgrand.net/2009/07/30/everybody-loves-the-sieve-of-eratosthenes/#comment-36 Here's my naive, ugly and untested take on the problem:<br />(defn not-divisible-by?[num denum]<br /> (not (= (mod num denum) 0)))<br /><br />(defn primes<br /> ([pos] (primes (vec (range 2 pos)) 0))<br /> ([clist pos]<br /> (cond<br /> (>= pos (count clist)) clist<br /> :else<br /> (let [val (nth clist pos)<br /> starting (inc pos)]<br /> (recur (into (subvec clist 0 starting) (vec (filter #(not-divisible-by? % val) (subvec clist starting (count clist))))) starting))))) Here's my naive, ugly and untested take on the problem:
(defn not-divisible-by?[num denum]
(not (= (mod num denum) 0)))

(defn primes
([pos] (primes (vec (range 2 pos)) 0))
([clist pos]
(cond
(>= pos (count clist)) clist
:else
(let [val (nth clist pos)
starting (inc pos)]
(recur (into (subvec clist 0 starting) (vec (filter #(not-divisible-by? % val) (subvec clist starting (count clist))))) starting)))))

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