bgmarx

def halve_array(arr)
  median = (arr.size / 2).round
  [arr.take(median), arr.drop(median)]
end

# a=*(1..100)
# b = halve_array(a)
# => [[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50], [51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]]
# b[0] = => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50]
# b[1] = => [51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]

bgmarx

def merge_sort(arr)
  return arr if arr.size <= 1
  
  left, right = halve_array(arr)
  left_part   = merge_sort(left)
  right_part  = merge_sort(right)

  array = []
  offset_left_part  = 0
  offset_right_part = 0

bgmarx

def chess_board(size = 8)
  i = 0
  j = 0
  while i < (size * size)
      if i % (size) == 0
        puts ""
        j % 2 == 0 ? print("# " * (size / 2)) : print(" #" * (size / 2))  
        j += 1
      end
    i += 1

bgmarx

def bubble_sort(list)
  return list if list.size <= 1
  swapped = true
  while swapped
    swapped = false
    0.upto(list.size-2) do |i|
      if(list[i] > list[i+1])
        list[i + 1], list[i] = list[i], list[i+1]
        swapped = true 
      end

bgmarx

(defn halve [a-seq]
  (let [half (int (/ (count a-seq))) 2]
  (vector (my-take half a-seq) (my-drop half a-seq))))

bgmarx

(defn my-take [n coll]
  (if (or (empty? coll)
          (zero? n))
    '()
  (cons (first coll) (my-take (dec n) (rest coll)))))

bgmarx

(defn my-drop [n coll]
  (if (or (empty? coll)
          (zero? n))
      coll
      (my-drop (dec n) (rest coll))))

bgmarx

(defn seq-merge [a-seq b-seq]
  (cond (empty? a-seq) b-seq
        (empty? b-seq) a-seq
        (> (first a-seq) (first b-seq))
          (cons (first b-seq) (seq-merge a-seq (rest b-seq)))
        :else (cons (first a-seq) (seq-merge b-seq (rest a-seq)))))

bgmarx

(defn merge-sort [a-seq]
  (cond (empty? a-seq) a-seq
        (singleton? a-seq) a-seq
        :else (let [[a b] (halve a-seq)]
          (seq-merge (merge-sort a)
                     (merge-sort b)))))
        

bgmarx

(defn singleton [coll]
  (and (not (empty? coll)) (empty? (rest coll))))