[Openmcl-devel] bit string matching

Andrew Shalit alms at clozure.com
Wed Jan 5 13:47:42 UTC 2011


Clojure and Common Lisp are two different programming languages.

Clozure Associates is a consulting company specializing in Common Lisp.

Clozure CL is an open source implementation of Common Lisp.



On Jan 5, 2011, at 8:38 AM, Lonnie Cumberland wrote:

> Greetings All,
> 
> Firstly, let me state that this is not any type of homework problem as
> was suggested by Lou earlier. I was namely in the process of seeing if
> a type of "max-palindrome" function already existed so that it would
> same me some time in having to re-code that part.
> 
> On the other side, I am running Clozure 1.6 from
> http://ccl.clozure.com/ on a Windows platform as well.
> 
> I just came across a couple of implementations, but could not seem to
> get them to run on Clozure ccl.
> 
> 
> FROM: http://osdir.com/ml/clojure/2010-10/msg00669.html
> -------------------------------------------------------------------
> (def st
> "FourscoreandsevenyearsagoourfaathersbroughtforthonthiscontainentanewnationconceivedinzLibertyanddedicatedtothepropositionthatallmenarecreatedequalNowweareengagedinagreahtcivilwartestingwhetherthatnaptionoranynartionsoconceivedandsodedicatedcanlongendureWeareqmetonagreatbattlefiemldoftzhatwarWehavecometodedicpateaportionofthatfieldasafinalrestingplaceforthosewhoheregavetheirlivesthatthatnationmightliveItisaltogetherfangandproperthatweshoulddothisButinalargersensewecannotdedicatewecannotconsecratewecannothallowthisgroundThebravelmenlivinganddeadwhostruggledherehaveconsecrateditfaraboveourpoorponwertoaddordetractTgheworldadswfilllittlenotlenorlongrememberwhatwesayherebutitcanneverforgetwhattheydidhereItisforusthelivingrathertobededicatedheretotheulnfinishedworkwhichtheywhofoughtherehavethusfarsonoblyadvancedItisratherforustobeherededicatedtothegreattdafskremainingbeforeusthatfromthesehonoreddeadwetakeincreaseddevotiontothatcauseforwhichtheygavethelastpfullmeasureofdevotionthatw
> eherehighlyresolvethatthesedeadshallnothavediedinvainthatthisnationunsderGodshallhaveanewbirthoffreedomandthatgovernmentofthepeoplebythepeopleforthepeopleshallnotperishfromtheearth")
> 
> (defn longest-palindrome-at [^String st ind1 ind2]
> 
> (let [ind1 (int ind1)
> ind2 (int ind2)]
> (if (= (.charAt st ind1)
> (.charAt st ind2))
> (if (or (zero? ind1) (= ind2 (dec (.length st))))
> [ind1 ind2]
> (recur st (dec ind1) (inc ind2)))
> [(inc ind1) (dec ind2)])))
> 
> (defn longest [^String st]
> (let [[ind1 ind2]
> (apply max-key (fn [[i1 i2]] (let [i1 (int i1) i2 (int i2)]
> (- i2 i1)))
> (concat
> (for [i (range (.length st))]
> (longest-palindrome-at st i i))
> (for [i (range 1 (.length st))]
> (longest-palindrome-at st (dec i) i))))]
> (.substring st ind1 (inc ind2))))
> ------------------------------------------------------------------
> 
> Any ideas on this?
> 
> Thanks in advance,
> Lonnie
> 
> On Tue, Jan 4, 2011 at 5:23 PM, Lou Vanek <lou.vanek at gmail.com> wrote:
>> Sorry, that's n^3 in time, not n^2. Space calc still holds.
>> _______________________________________________
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>> Openmcl-devel at clozure.com
>> http://clozure.com/mailman/listinfo/openmcl-devel
>> 
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