2024-09-26 v. 6.6.9: added "208. Implement Trie (Prefix Tree)"

.rubocop.yml

@@ -52,3 +52,5 @@ Lint/NumberConversion:
   Enabled: false
 Lint/DuplicateBranch:
   Enabled: false
+Lint/UselessSetterCall:
+  Enabled: false

README.md

@@ -534,3 +534,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 199. Binary Tree Right Side View                                | [Link](https://leetcode.com/problems/binary-tree-right-side-view/)                                | [Link](./lib/medium/199_binary_tree_right_side_view.rb)                                | [Link](./test/medium/test_199_binary_tree_right_side_view.rb)                                |
 | 200. Number of Islands                                          | [Link](https://leetcode.com/problems/number-of-islands/)                                          | [Link](./lib/medium/200_number_of_islands.rb)                                          | [Link](./test/medium/test_200_number_of_islands.rb)                                          |
 | 204. Count Primes                                               | [Link](https://leetcode.com/problems/count-primes/)                                               | [Link](./lib/medium/204_count_primes.rb)                                               | [Link](./test/medium/test_204_count_primes.rb)                                               |
+| 208. Implement Trie (Prefix Tree)                               | [Link](https://leetcode.com/problems/implement-trie-prefix-tree/)                                 | [Link](./lib/medium/208_implement_trie_prefix_tree.rb)                                 | [Link](./test/medium/test_208_implement_trie_prefix_tree.rb)                                 |

leetcode-ruby.gemspec

@@ -5,7 +5,7 @@ require 'English'
 ::Gem::Specification.new do |s|
   s.required_ruby_version = '>= 3.0'
   s.name = 'leetcode-ruby'
-  s.version = '6.6.8'
+  s.version = '6.6.9'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/208_implement_trie_prefix_tree.rb

@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/implement-trie-prefix-tree/
+class Trie
+  # Init
+  def initialize
+    @root = ::Node208.new
+  end
+
+  # @param {String} word
+  # @return {Void}
+  def insert(word)
+    curr = @root
+    word.each_char do |c|
+      node = curr.children[c]
+
+      unless node
+        node = ::Node208.new
+        curr.children[c] = node
+      end
+
+      curr = node
+    end
+
+    curr.nd = true
+  end
+
+  # @param {String} word
+  # @return {Boolean}
+  def search(word)
+    curr = @root
+    word.each_char do |c|
+      node = curr.children[c]
+
+      return false unless node
+
+      curr = node
+    end
+
+    curr.nd
+  end
+
+  # @param {String} word
+  # @return {Boolean}
+  def starts_with(prefix)
+    curr = @root
+    prefix.each_char do |c|
+      node = curr.children[c]
+
+      return false unless node
+
+      curr = node
+    end
+
+    true
+  end
+end
+
+private
+
+# Node for Trie
+class Node208
+  attr_accessor :children, :nd
+
+  # Init
+  def initialize
+    @children = {}
+    @nd = false
+  end
+end

test/medium/test_208_implement_trie_prefix_tree.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/208_implement_trie_prefix_tree'
+require 'minitest/autorun'
+
+class CountPrimesTest < ::Minitest::Test
+  def test_default_one
+    trie = ::Trie.new
+
+    trie.insert('apple')
+    assert(trie.search('apple'))
+    assert(!trie.search('app'))
+    assert(trie.starts_with('app'))
+
+    trie.insert('app')
+    assert(trie.search('app'))
+  end
+end