Programming Kata Day 7

1 minute read

Code kata

Problem

Suppose a binary tree structure looks like this:

{:val value :L <left-node> :R <right-node>}

Write a function to balance insert node into the tree.

Solution

(defn insert [tree x]
  (cond (nil? tree)
        {:val x :L nil :R nil}

        (< x (:val tree))
        (assoc tree :L (insert (:L tree) x))

        :else
        (assoc tree :R (insert (:R tree) x))))

Note

Here is the function to traverse the tree:

(defn traverse [tree]
  (when tree
    (concat (traverse (:L tree)) [(:val tree)] (traverse (:R tree)))))

Here is a helper function to create a tree.

(defn create-tree [& xs]
  (reduce (fn [result next] (xconj result next)) nil xs))
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