anagrams.clj

;; http://codekata.pragprog.com/2007/01/kata_six_anagra.html

(ns user
  (:use [clojure.string :only [join split-lines lower-case]]))

;; map of normalized (with sorted letters) word to set of anagrams
(def anagram-map
  (let [words (split-lines (slurp "/usr/share/dict/words"))]
    (reduce
     (fn [m word]
       (let [normword (join (sort (lower-case word)))]
         (assoc m
           normword (conj (m normword #{}) word))))
     {}
     words)))

(def anagrams
  (filter #(< 1 (count %))
          (vals anagram-map)))

;; http://groups.google.com/group/clojure/browse_thread/thread/ca715954a42655bd

(def top-10
  (take 10 (sort-by (comp count val) > anagram-map)))

(doseq [[normword anagrams] top-10]
  (println (count anagrams) normword ":" anagrams))