Fun with Zodiac signs

November 22, 2010 · 7 Comments

Here's a little puzzler for you! Given the twelve signs of the zodiac, write some code to print out a list of all the valid keys / pairs such that:

The keys have the form: zodiac.firstsign.secondsign (all lowercase)
The values have the form Firstsign and Secondsign (correct case on the sign names)
firstsign and secondsign are in alphabetical order
There are no duplicates

The result will have lines like:

[zodiac.aquarius.aquarius Aquarius and Aquarius]
[zodiac.aquarius.pisces Aquarius and Pisces]
...
[zodiac.aries.pisces Aries and Pisces]
[zodiac.aries.aries Aries and Aries]
[zodiac.aries.taurus Aries and Taurus]
...

Here's the solution I came up with in Clojure:

(def z ["Aquarius" "Pisces" "Aries" "Taurus" "Gemini" "Cancer" "Leo" "Virgo" "Libra" "Scorpio" "Sagittarius" "Capricorn"])
(defn zkey[a b] [(str "zodiac." (.toLowerCase a) "." (.toLowerCase b)) (str a " and " b)])
(defn accept[a b] (<= (.compareTo a b) 0))
(defn zkeys[s] (map (partial zkey s) (filter (partial accept s) z)))
(map println (mapcat zkeys z))

The zkey function creates the key / value strings from a pair of signs. The accept function is a predicate that returns true if and only if sign a is alphabetically no greater than sign b. The zkeys function returns the set of key / value pairs for a given sign (against the full list of signs). Finally the last line applies zkeys across the full list of signs and prints the result - mapcat just flattens the results one level to make it easier to read.

If you think you have a better solution (in any language), feel free to post it as a comment!

View count: 20530

Tags: clojure · coldfusion · programming

7 responses so far ↓

1 Marlon // Nov 22, 2010 at 3:46 PM

not better, just different :)

z = %w(Aquarius Pisces Aries Taurus Gemini Cancer Leo Virgo Libra Scorpio Sagittarius Capricorn)

z.map {|sign| z.map {|sign2| [sign, sign2].sort.join(".")}}.flatten.uniq.each {|combo| puts "zodiac.#{combo.downcase} #{combo.gsub('.',' and ')}"}
2 hsanjeewa // Nov 22, 2010 at 4:12 PM

(use '[clojure.string :only (lower-case)])

(doseq [[fst snd] (for [z1 z z2 z :when (>= 0 (compare z1 z2))] [z1 z2])]
(println (lower-case (str "zodiac." fst "." snd)) fst " and " snd))
3 Barney Boisvert // Nov 22, 2010 at 4:26 PM

Here's some Groovy:

z = ['Aquarius', 'Pisces', 'Aries', 'Taurus', 'Gemini', 'Cancer', 'Leo', 'Virgo', 'Libra', 'Scorpio', 'Sagittarius', 'Capricorn']
map = [:]
z.sort().each { a ->
   z.sort().findAll {
      it >= a
   }.each { b ->
      map["zodiac.${a.toLowerCase()}.${b.toLowerCase()}"] = "$a and $b"
   }
}
println map
4 brandon // Nov 22, 2010 at 5:08 PM

how about this:

(defn combos []
(for [x z
y z
:when (accept x y)]
(zkey x y)))

(clojure.pprint/pprint (combos))
5 Michael Kohl // Nov 23, 2010 at 2:43 AM

Ruby:

z = %w(Aquarius Pisces Aries Taurus Gemini Cancer Leo Virgo Libra Scorpio Sagittarius Capricorn)

z.combination(2).each { |combo| p ["zodiac.#{combo.join('.').downcase} #{combo[0].capitalize} and #{combo[1].capitalize}"] }
6 brandon // Nov 23, 2010 at 4:42 AM

comment moderation makes me look like a plagiarizer.

: )
7 Sean Corfield // Nov 23, 2010 at 10:19 PM

@brandon, yeah, I got four responses very quickly after I posted it, before I got time to approve them! I keep forgetting about 'for' in Clojure... it would make several of my functions much cleaner!

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