kertotaulu

(ns experimentation.kertotaulu
  (:require
   [clojure.string :as string]))

(defn multiplications [numbers]
  (mapcat (fn [a]
            (for [b numbers]
              [a b]))
          numbers))

(comment
  (doseq [table (partition-by first (->> (multiplications (range 1 11))
                                         (map sort)
                                         (distinct)))]
    (println)
    (doseq [[a b] table]
      (println (str a " * " b " = " (* a b)))))

  (do
    (println (string/join "\t" (range 1 11)))
    (println)
    (doseq [number (range 1 101)]
      (println (string/join "\t"
                            (for [maximum-multiplier (range 1 11)]
                              (str number
                                   (when (contains? (->> (multiplications (range 1 (inc maximum-multiplier)))
                                                         (map (partial apply *))
                                                         (set))
                                                    number)
                                     "*")))))))

  )