chess_problem.clj

(ns chess-problem)
  ;; (:require [clojure.contrib.seq-utils :as s-utils]))

;; Backrow of the chess board.
;; Bishops are on different colours.
;; King has to be between the rooks.
;; A function that takes a number n
;; And returns n valid backrows.

(def std-backrow [:r :kn :b :ki :q :b :kn :r])
(def inv-backrow [:r :kn :b :ki :b :q :kn :r])

(defn gen-backrow []
  (shuffle std-backrow))

(gen-backrow)

(defn gen-backrows []
  (repeatedly gen-backrow))

(defn many-backrows [number]
  (take number (gen-backrows)))

(defn bishop-index [row]
  (keep-indexed
   (fn [idx val] (when (= :b val) idx))
   row))

(defn valid-bishops [row]
  (odd? (apply - (bishop-index row))))

(valid-bishops std-backrow)
(valid-bishops inv-backrow)

(defn valid-king [row]
  )

;; (many-backrows 5)

;; (index :a [:a :b])

;; (defn indexes [index item pred]
;;   (if (my-pred item)
;;     index
;;     nil))

;; (defn my-pred [item]
;;     (= :b item))

;; (keep-indexed #(indexes % %2 my-pred)
;;  std-backrow)