Finding min path with brute force

min-path.clj

(defn min-path [ivec]
  (letfn [(expand [in]
            (loop [n 0 acc [[0]]]
              (if (= n in)
                acc
                (recur
                  (inc n)
                  (reduce
                    concat
                    (#(map (fn [n] [(cons 0 n) (cons 0 (map inc n))]) %) acc))))))]
    (apply min (map
                 #(reduce + %)
                 (map
                   #(map (fn [[k v]] (nth (nth ivec k) v)) %)
                   (map #(zipmap (range) %) (expand (dec (count ivec))))))))
  )

(= 7 (min-path '([1]
                [2 4]
               [5 1 4]
              [2 3 4 5]))) ; 1->2->1->3
; true

(= 20 (min-path '([3]
                 [2 4]
                [1 9 3]
               [9 9 2 4]
              [4 6 6 7 8]
             [5 7 3 5 1 4]))) ; 3->4->3->2->7->1
; true