chrisvest-4clojure-solution66.clj

;; chrisvest's solution to http://4clojure.com/problem/66

;; Using Euclid's algorithm
(fn gcd [a b]
  (loop [dividend (max a b)
         divisor (min a b)
         quotient (quot dividend divisor)
         remainder (rem dividend divisor)]
    (if (zero? remainder)
      divisor
      (recur divisor
             remainder
             (quot divisor remainder)
             (rem divisor remainder)))))

I just translated Wikipedia's definition of Euclid's algorithm and end up with this:

(fn gcd [a b]
  (if (= b 0) a
    (gcd b (mod a b))))

I guess you went the loop/recur way to avoid a stack overflow, right (which I didn't think about)? So... this seems to do it.

(fn gcd [a b]
  (loop [a a b b]
    (if (zero? b) a
        (recur b (mod a b)))))

Nice!
I translated from another article that tried to explain how the algorithm worked in detail, so I guess it's no wonder that my version ended up over-engineered.