Returning Level-1 Node In a Balanced Binary Search Tree Ruby?

I am recursively creating a balanced binary search tree in Ruby using a sorted array. However, I'm having trouble at the ending return value. Instead of all the nodes bubbling up, creating a tree and returning the base level 1 node, the very last node at the bottom of the tree is returned.

It doesn't seem like the nodes being created are linked together at all (printing the instantiated class using p list only returns the last node). How do I link the nodes together and return the level 1 root node?

Code:

class Node    include Comparable      attr_accessor :value, :left, :right      def initialize(value, left = nil, right = nil)      @value = value      @left = left      @right = right    end  end    class Tree    attr_accessor :sorted_arr, :arr      def initialize(arr)      @arr = arr      @sorted_arr = arr.sort.uniq    end      #Problem: nodes not being linked together      def build_tree(arr, start, last)      if start > last        return nil      end        mid_index = (start + last) / 2            @root = Node.new(arr[mid_index])          @root.left = build_tree(arr, start, mid_index - 1)      @root.right = build_tree(arr, mid_index + 1, last)          return @root    end  end    list = Tree.new([1, 7, 4, 23, 8, 9, 4, 3, 6, 7, 9, 67, 6345, 324])  list.build_tree(list.sorted_arr, 0, list.sorted_arr.length-1)  p list      

https://stackoverflow.com/questions/67308470/returning-level-1-node-in-a-balanced-binary-search-tree-ruby April 29, 2021 at 05:59AM