Clojure Golf: fib-seq
Revisiting a classic:
(def fib-seq
(lazy-cat [0 1] (map + fib-seq (rest fib-seq))))
Clojure Golf: subsets-by-card (2)
I wasn’t happy with the last one. At least this one is lazier and in increasing cardinality order.
(defn subsets-by-card [s]
(reduce (fn [ssbc x]
(map (fn [a b] (concat a (map #(conj % x) b)))
(concat ssbc [nil]) (concat [nil] ssbc)))
[[#{}]] s))
Decreasing order:
(defn subsets-by-card-reverse [s]
(reduce (fn [ssbc x]
(map (fn [a b] (concat a (map #(<ins>disj</ins> % x) b)))
(concat ssbc [nil]) (concat [nil] ssbc)))
[[<ins>(set s)</ins>]] s))
Clojure Golf: subsets-by-card
(defn subsets-by-card [s]
(reduce (fn [ssbc x]
(concat
(map (fn [a b] (concat a (map #(conj % x) b)))
(cons nil ssbc) ssbc)
[[#{}]]))
[[#{}]] s))
(a tough one)
Clojure Golf: subsets
(defn subsets [s]
(reduce (fn [ss x] (concat ss (map #(conj % x) ss))) [#{}] s))
Clojure Golf: combinations (2)
(defn combinations [& cs]
(reduce #(for [v %1 i %2] (conj v i)) [[]] cs))
Clojure Golf: combinations
(defn combinations [& cs]
(reduce (fn [vs c]
(mapcat #(map conj vs (repeat %)) c))
[[]] cs))
