Recursion 101

In this Kata, you will be given two positive integers a and b and your task will be to apply the following operations:

當 a = 0 || b = 0 時回傳 [a, b]，否則重複 step 2 & 3 計算

i) If a = 0 or b = 0, return [a,b]. Otherwise, go to step (ii);
ii) If a ≥ 2*b, set a = a - 2*b, and repeat step (i). Otherwise, go to step (iii);
iii) If b ≥ 2*a, set b = b - 2*a, and repeat step (i). Otherwise, return [a,b].

Solution

(ns kata.core)

(defn solve [a b]
  (cond 
    (or (zero? a) (zero? b)) (list a b)
    (>= a (* 2 b)) (solve (- a (* 2 b)) b)
    (>= b (* 2 a)) (solve a (- b (* 2 a)))
    :else (list a b)))