Edd Mann Developer

Bubble-sort in Clojure

Following on with my exploration into implementing common sorting algorithms in Clojure, today we have the Bubble-sort. This sort works by iteratively passing through the supplied sequence, swapping the current element with the next if it is comparably greater. The operation is complete when a pass through the sequence does not result in a swap occurring.

(defn- bubble [ys x]
(if-let [y (peek ys)]
(if (> y x)
(conj (pop ys) x y)
(conj ys x))

(defn bubble-sort [xs]
(let [ys (reduce bubble [] xs)]
(if (= xs ys)
(recur ys))))

(bubble-sort [3 2 1]) ; [1 2 3]

Looking at the implementation above you will notice we use a reduce operation with a private bubble function which provides us with the pass through the sequence. Upon each pass the result is checked against the input to see if a swap has occurred, in the case of them both being equal we have completed the sorting process.