gistfile1.txt

(ns dojo.core
  (:use [clojure.set]
        [clojure.java.io]))

(def digits [
  "    _  _     _  _  _  _  _ "
  "  | _| _||_||_ |_   ||_||_|"
  "  ||_  _|  | _||_|  ||_| _|"])

(defn read-file [rdr]
    (line-seq rdr))


(defn chunk-in-threes [line]
  (partition 9 line))

;(doall (map println digits))

(defn nth-digit [lines n]
"0-indexed."
(let [x (* 3 n)
      x2 (+ 3 x)
      chunks (for [y (range 3)] (subs (nth lines y) x x2))]
  (vec chunks)))

;(doall (map #(println (nth-digit digits %)) (range 9)))

(def input-file "/Users/nchubrich/numbers.txt")

(defn parse-line-1 [line]
  (cond (= " _ " line) #{2 3 5 6 7 8 9}
        (= "   " line) #{1 4}))

(defn parse-line-2 [line]
  (cond (= line "  |") #{1 7}
        (= line " _|") #{2 3}
        (= line "|_ ") #{5 6}
        (= line "|_|") #{4 8 9}))
           
(defn parse-line-3 [line]
  (cond (= line "  |") #{1 7 4}
        (= line " _|") #{3 5 9}
        (= line "|_ ") #{2}
        (= line "|_|") #{6 8}))

(defn parse-cell [cell]
  (first (intersection (parse-line-1 (cell 0)) (parse-line-2 (cell 1)) (parse-line-3 (cell 2)))))

(with-open [rdr (reader input-file)]
  (let [lines (read-file rdr)
        chunked-lines (chunk-in-threes (doall lines))]
    (map (fn [line index] (parse-cell (nth-digit line index))) chunked-lines (range 0 9))))