rubyx01.md

I'm looking at https://en.wikipedia.org/wiki/Trie#A_Ruby_version

Line 9 seems useless since line 10 is there. For each character in the string, create a key,value pair where the key is the character and the value is a new hash. If the key has been created, assign it a value of the character instead of an empty hash, but then the very next line the parent hash is set to either an empty hash or a character. It doesn't seem right for some reason, and I was hoping someone here with a little time on their hands would slap some sense into me

trie.rb

class Trie
  def initialize
    @root = Hash.new
  end
 
  def build(str) 
    node = @root    
    str.each_char do |ch|
      node[ch] ||= Hash.new
      node = node[ch]
    end
    node[:end] = true
  end
 
  def find(str) 
    node = @root
    str.each_char do |ch|
      return nil unless node = node[ch]
    end
    node[:end] && true
  end
end