Problem Four - Programming problems software engineers should be able to solve

four.clj

;; https://blog.svpino.com/2015/05/07/five-programming-problems-every-software-engineer-should-be-able-to-solve-in-less-than-1-hour
;; problem four, not all that pretty

(defn numseq [x]
   (map (comp read-string str) (str x)))

(defn strsort [x 
               y]
  (let [a (first x)
        b (first y)]                                
    (cond 
     (and (not a) (not b)) 0
     (not b) 1
     (not a) -1
     (> a b) -1
     (< a b) 1
     :else (strsort (rest x) (rest y)))))

(defn biggest [nums]
    (apply str (map #(apply str %) 
                    (sort strsort
                     (map numseq nums)))))

(biggest [5 55 50])