Translate all code to English (#1836)

* Review the EN heading format.

* Fix pythontutor headings.

* Fix pythontutor headings.

* bug fixes

* Fix headings in **/summary.md

* Revisit the CN-to-EN translation for Python code using Claude-4.5

* Revisit the CN-to-EN translation for Java code using Claude-4.5

* Revisit the CN-to-EN translation for Cpp code using Claude-4.5.

* Fix the dictionary.

* Fix cpp code translation for the multipart strings.

* Translate Go code to English.

* Update workflows to test EN code.

* Add EN translation for C.

* Add EN translation for CSharp.

* Add EN translation for Swift.

* Trigger the CI check.

* Revert.

* Update en/hash_map.md

* Add the EN version of Dart code.

* Add the EN version of Kotlin code.

* Add missing code files.

* Add the EN version of JavaScript code.

* Add the EN version of TypeScript code.

* Fix the workflows.

* Add the EN version of Ruby code.

* Add the EN version of Rust code.

* Update the CI check for the English version  code.

* Update Python CI check.

* Fix cmakelists for en/C code.

* Fix Ruby comments

en/codes/ruby/chapter_tree/array_binary_tree.rb

@@ -0,0 +1,124 @@
+=begin
+File: array_binary_tree.rb
+Created Time: 2024-04-17
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+require_relative '../utils/tree_node'
+require_relative '../utils/print_util'
+
+### Array representation of binary tree class ###
+class ArrayBinaryTree
+  ### Constructor ###
+  def initialize(arr)
+    @tree = arr.to_a
+  end
+
+  ### List capacity ###
+  def size
+    @tree.length
+  end
+
+  ### Get value of node at index i ###
+  def val(i)
+    # Return nil if index out of bounds, representing empty position
+    return if i < 0 || i >= size
+
+    @tree[i]
+  end
+
+  ### Get left child index of node at index i ###
+  def left(i)
+    2 * i + 1
+  end
+
+  ### Get right child index of node at index i ###
+  def right(i)
+    2 * i + 2
+  end
+
+  ### Get parent node index of node at index i ###
+  def parent(i)
+    (i - 1) / 2
+  end
+
+  ### Level-order traversal ###
+  def level_order
+    @res = []
+
+    # Traverse array directly
+    for i in 0...size
+      @res << val(i) unless val(i).nil?
+    end
+
+    @res
+  end
+
+  ### Depth-first traversal ###
+  def dfs(i, order)
+    return if val(i).nil?
+    # Preorder traversal
+    @res << val(i) if order == :pre
+    dfs(left(i), order)
+    # Inorder traversal
+    @res << val(i) if order == :in
+    dfs(right(i), order)
+    # Postorder traversal
+    @res << val(i) if order == :post
+  end
+
+  ### Pre-order traversal ###
+  def pre_order
+    @res = []
+    dfs(0, :pre)
+    @res
+  end
+
+  ### In-order traversal ###
+  def in_order
+    @res = []
+    dfs(0, :in)
+    @res
+  end
+
+  ### Post-order traversal ###
+  def post_order
+    @res = []
+    dfs(0, :post)
+    @res
+  end
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  # Initialize binary tree
+  # Here we use a function to generate a binary tree directly from an array
+  arr = [1, 2, 3, 4, nil, 6, 7, 8, 9, nil, nil, 12, nil, nil, 15]
+  root = arr_to_tree(arr)
+  puts "\nInitialize binary tree\n\n"
+  puts 'Array representation of binary tree:'
+  pp arr
+  puts 'Linked list representation of binary tree:'
+  print_tree(root)
+
+  # Binary tree class represented by array
+  abt = ArrayBinaryTree.new(arr)
+
+  # Access node
+  i = 1
+  l, r, _p = abt.left(i), abt.right(i), abt.parent(i)
+  puts "\nCurrent node index is #{i}, value is #{abt.val(i).inspect}"
+  puts "Left child index is #{l}, value is #{abt.val(l).inspect}"
+  puts "Right child index is #{r}, value is #{abt.val(r).inspect}"
+  puts "Parent node index is #{_p}, value is #{abt.val(_p).inspect}"
+
+  # Traverse tree
+  res = abt.level_order
+  puts "\nLevel-order traversal is: #{res}"
+  res = abt.pre_order
+  puts "Pre-order traversal is: #{res}"
+  res = abt.in_order
+  puts "In-order traversal is: #{res}"
+  res = abt.post_order
+  puts "Post-order traversal is: #{res}"
+end

en/codes/ruby/chapter_tree/avl_tree.rb

@@ -0,0 +1,216 @@
+=begin
+File: avl_tree.rb
+Created Time: 2024-04-17
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+require_relative '../utils/tree_node'
+require_relative '../utils/print_util'
+
+### AVL tree ###
+class AVLTree
+  ### Constructor ###
+  def initialize
+    @root = nil
+  end
+
+  ### Get binary tree root node ###
+  def get_root
+    @root
+  end
+
+  ### Get node height ###
+  def height(node)
+    # Empty node height is -1, leaf node height is 0
+    return node.height unless node.nil?
+
+    -1
+  end
+
+  ### Update node height ###
+  def update_height(node)
+    # Node height equals the height of the tallest subtree + 1
+    node.height = [height(node.left), height(node.right)].max + 1
+  end
+
+  ### Get balance factor ###
+  def balance_factor(node)
+    # Empty node balance factor is 0
+    return 0 if node.nil?
+
+    # Node balance factor = left subtree height - right subtree height
+    height(node.left) - height(node.right)
+  end
+
+  ### Right rotation ###
+  def right_rotate(node)
+    child = node.left
+    grand_child = child.right
+    # Using child as pivot, rotate node to the right
+    child.right = node
+    node.left = grand_child
+    # Update node height
+    update_height(node)
+    update_height(child)
+    # Return root node of subtree after rotation
+    child
+  end
+
+  ### Left rotation ###
+  def left_rotate(node)
+    child = node.right
+    grand_child = child.left
+    # Using child as pivot, rotate node to the left
+    child.left = node
+    node.right = grand_child
+    # Update node height
+    update_height(node)
+    update_height(child)
+    # Return root node of subtree after rotation
+    child
+  end
+
+  ### Perform rotation to rebalance subtree ###
+  def rotate(node)
+    # Get balance factor of node
+    balance_factor = balance_factor(node)
+    # Left-heavy tree
+    if balance_factor > 1
+      if balance_factor(node.left) >= 0
+        # Right rotation
+        return right_rotate(node)
+      else
+        # First left rotation then right rotation
+        node.left = left_rotate(node.left)
+        return right_rotate(node)
+      end
+    # Right-heavy tree
+    elsif balance_factor < -1
+      if balance_factor(node.right) <= 0
+        # Left rotation
+        return left_rotate(node)
+      else
+        # First right rotation then left rotation
+        node.right = right_rotate(node.right)
+        return left_rotate(node)
+      end
+    end
+    # Balanced tree, no rotation needed, return directly
+    node
+  end
+
+  ### Insert node ###
+  def insert(val)
+    @root = insert_helper(@root, val)
+  end
+
+  ### Recursively insert node (helper method) ###
+  def insert_helper(node, val)
+    return TreeNode.new(val) if node.nil?
+    # 1. Find insertion position and insert node
+    if val < node.val
+      node.left = insert_helper(node.left, val)
+    elsif val > node.val
+      node.right = insert_helper(node.right, val)
+    else
+      # Duplicate node not inserted, return directly
+      return node
+    end
+    # Update node height
+    update_height(node)
+    # 2. Perform rotation operation to restore balance to this subtree
+    rotate(node)
+  end
+
+  ### Delete node ###
+  def remove(val)
+    @root = remove_helper(@root, val)
+  end
+
+  ### Recursively delete node (helper method) ###
+  def remove_helper(node, val)
+    return if node.nil?
+    # 1. Find node and delete
+    if val < node.val
+      node.left = remove_helper(node.left, val)
+    elsif val > node.val
+      node.right = remove_helper(node.right, val)
+    else
+      if node.left.nil? || node.right.nil?
+        child = node.left || node.right
+        # Number of child nodes = 0, delete node directly and return
+        return if child.nil?
+        # Number of child nodes = 1, delete node directly
+        node = child
+      else
+        # Number of child nodes = 2, delete the next node in inorder traversal and replace current node with it
+        temp = node.right
+        while !temp.left.nil?
+          temp = temp.left
+        end
+        node.right = remove_helper(node.right, temp.val)
+        node.val = temp.val
+      end
+    end
+    # Update node height
+    update_height(node)
+    # 2. Perform rotation operation to restore balance to this subtree
+    rotate(node)
+  end
+
+  ### Search node ###
+  def search(val)
+    cur = @root
+    # Loop search, exit after passing leaf node
+    while !cur.nil?
+      # Target node is in cur's right subtree
+      if cur.val < val
+        cur = cur.right
+      # Target node is in cur's left subtree
+      elsif cur.val > val
+        cur = cur.left
+      # Found target node, exit loop
+      else
+        break
+      end
+    end
+    # Return target node
+    cur
+  end
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  def test_insert(tree, val)
+    tree.insert(val)
+    puts "\nAfter inserting node #{val}, AVL tree is"
+    print_tree(tree.get_root)
+  end
+
+  def test_remove(tree, val)
+    tree.remove(val)
+    puts "\nAfter deleting node #{val}, AVL tree is"
+    print_tree(tree.get_root)
+  end
+
+  # Please pay attention to how the AVL tree maintains balance after inserting nodes
+  avl_tree = AVLTree.new
+
+  # Insert node
+  # Delete nodes
+  for val in [1, 2, 3, 4, 5, 8, 7, 9, 10, 6]
+    test_insert(avl_tree, val)
+  end
+
+  # Please pay attention to how the AVL tree maintains balance after deleting nodes
+  test_insert(avl_tree, 7)
+
+  # Remove node
+  # Delete node with degree 1
+  test_remove(avl_tree, 8) # Delete node with degree 2
+  test_remove(avl_tree, 5) # Remove node with degree 1
+  test_remove(avl_tree, 4) # Remove node with degree 2
+
+  result_node = avl_tree.search(7)
+  puts "\nFound node object #{result_node}, node value = #{result_node.val}"
+end

en/codes/ruby/chapter_tree/binary_search_tree.rb

@@ -0,0 +1,161 @@
+=begin
+File: binary_search_tree.rb
+Created Time: 2024-04-18
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+require_relative '../utils/tree_node'
+require_relative '../utils/print_util'
+
+### Binary search tree ###
+class BinarySearchTree
+  ### Constructor ###
+  def initialize
+    # Initialize empty tree
+    @root = nil
+  end
+
+  ### Get binary tree root node ###
+  def get_root
+    @root
+  end
+
+  ### Search node ###
+  def search(num)
+    cur = @root
+
+    # Loop search, exit after passing leaf node
+    while !cur.nil?
+      # Target node is in cur's right subtree
+      if cur.val < num
+        cur = cur.right
+      # Target node is in cur's left subtree
+      elsif cur.val > num
+        cur = cur.left
+      # Found target node, exit loop
+      else
+        break
+      end
+    end
+
+    cur
+  end
+
+  ### Insert node ###
+  def insert(num)
+    # If tree is empty, initialize root node
+    if @root.nil?
+      @root = TreeNode.new(num)
+      return
+    end
+
+    # Loop search, exit after passing leaf node
+    cur, pre = @root, nil
+    while !cur.nil?
+      # Found duplicate node, return directly
+      return if cur.val == num
+
+      pre = cur
+      # Insertion position is in cur's right subtree
+      if cur.val < num
+        cur = cur.right
+      # Insertion position is in cur's left subtree
+      else
+        cur = cur.left
+      end
+    end
+
+    # Insert node
+    node = TreeNode.new(num)
+    if pre.val < num
+      pre.right = node
+    else
+      pre.left = node
+    end
+  end
+
+  ### Delete node ###
+  def remove(num)
+    # If tree is empty, return directly
+    return if @root.nil?
+
+    # Loop search, exit after passing leaf node
+    cur, pre = @root, nil
+    while !cur.nil?
+      # Found node to delete, exit loop
+      break if cur.val == num
+
+      pre = cur
+      # Node to delete is in cur's right subtree
+      if cur.val < num
+        cur = cur.right
+      # Node to delete is in cur's left subtree
+      else
+        cur = cur.left
+      end
+    end
+    # If no node to delete, return directly
+    return if cur.nil?
+
+    # Number of child nodes = 0 or 1
+    if cur.left.nil? || cur.right.nil?
+      # When number of child nodes = 0 / 1, child = null / that child node
+      child = cur.left || cur.right
+      # Delete node cur
+      if cur != @root
+        if pre.left == cur
+          pre.left = child
+        else
+          pre.right = child
+        end
+      else
+        # If deleted node is root node, reassign root node
+        @root = child
+      end
+    # Number of child nodes = 2
+    else
+      # Get next node of cur in inorder traversal
+      tmp = cur.right
+      while !tmp.left.nil?
+        tmp = tmp.left
+      end
+      # Recursively delete node tmp
+      remove(tmp.val)
+      # Replace cur with tmp
+      cur.val = tmp.val
+    end
+  end
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  # Initialize binary search tree
+  bst = BinarySearchTree.new
+  nums = [8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15]
+  # Please note that different insertion orders will generate different binary trees, this sequence can generate a perfect binary tree
+  nums.each { |num| bst.insert(num) }
+  puts "\nInitialized binary tree is\n"
+  print_tree(bst.get_root)
+
+  # Search node
+  node = bst.search(7)
+  puts "\nFound node object: #{node}, node value = #{node.val}"
+
+  # Insert node
+  bst.insert(16)
+  puts "\nAfter inserting node 16, binary tree is\n"
+  print_tree(bst.get_root)
+
+  # Remove node
+  bst.remove(1)
+  puts "\nAfter removing node 1, binary tree is\n"
+  print_tree(bst.get_root)
+
+  bst.remove(2)
+  puts "\nAfter removing node 2, binary tree is\n"
+  print_tree(bst.get_root)
+
+  bst.remove(4)
+  puts "\nAfter removing node 4, binary tree is\n"
+  print_tree(bst.get_root)
+end

en/codes/ruby/chapter_tree/binary_tree.rb

@@ -0,0 +1,38 @@
+=begin
+File: binary_tree.rb
+Created Time: 2024-04-18
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+require_relative '../utils/tree_node'
+require_relative '../utils/print_util'
+
+### Driver Code ###
+if __FILE__ == $0
+  # Initialize binary tree
+  # Initialize nodes
+  n1 = TreeNode.new(1)
+  n2 = TreeNode.new(2)
+  n3 = TreeNode.new(3)
+  n4 = TreeNode.new(4)
+  n5 = TreeNode.new(5)
+  # Build references (pointers) between nodes
+  n1.left = n2
+  n1.right = n3
+  n2.left = n4
+  n2.right = n5
+  puts "\nInitialize binary tree\n\n"
+  print_tree(n1)
+
+  # Insert node P between n1 -> n2
+  _p = TreeNode.new(0)
+  # Insert node _p between n1 -> n2
+  n1.left = _p
+  _p.left = n2
+  puts "\nAfter inserting node _p\n\n"
+  print_tree(n1)
+  # Remove node
+  n1.left = n2
+  puts "\nAfter deleting node _p\n\n"
+  print_tree(n1)
+end

en/codes/ruby/chapter_tree/binary_tree_bfs.rb

@@ -0,0 +1,36 @@
+=begin
+File: binary_tree_bfs.rb
+Created Time: 2024-04-18
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+require_relative '../utils/tree_node'
+require_relative '../utils/print_util'
+
+### Level-order traversal ###
+def level_order(root)
+  # Initialize queue, add root node
+  queue = [root]
+  # Initialize a list to save the traversal sequence
+  res = []
+  while !queue.empty?
+    node = queue.shift # Dequeue
+    res << node.val # Save node value
+    queue << node.left unless node.left.nil? # Left child node enqueue
+    queue << node.right unless node.right.nil? # Right child node enqueue
+  end
+  res
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  # Initialize binary tree
+  # Here we use a function to generate a binary tree directly from an array
+  root = arr_to_tree([1, 2, 3, 4, 5, 6, 7])
+  puts "\nInitialize binary tree\n\n"
+  print_tree(root)
+
+  # Level-order traversal
+  res = level_order(root)
+  puts "\nLevel-order traversal node sequence = #{res}"
+end

en/codes/ruby/chapter_tree/binary_tree_dfs.rb

@@ -0,0 +1,62 @@
+=begin
+File: binary_tree_dfs.rb
+Created Time: 2024-04-18
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+require_relative '../utils/tree_node'
+require_relative '../utils/print_util'
+
+### Pre-order traversal ###
+def pre_order(root)
+  return if root.nil?
+
+  # Visit priority: root node -> left subtree -> right subtree
+  $res << root.val
+  pre_order(root.left)
+  pre_order(root.right)
+end
+
+### In-order traversal ###
+def in_order(root)
+  return if root.nil?
+
+  # Visit priority: left subtree -> root node -> right subtree
+  in_order(root.left)
+  $res << root.val
+  in_order(root.right)
+end
+
+### Post-order traversal ###
+def post_order(root)
+  return if root.nil?
+
+  # Visit priority: left subtree -> right subtree -> root node
+  post_order(root.left)
+  post_order(root.right)
+  $res << root.val
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  # Initialize binary tree
+  # Here we use a function to generate a binary tree directly from an array
+  root = arr_to_tree([1, 2, 3, 4, 5, 6, 7])
+  puts "\nInitialize binary tree\n\n"
+  print_tree(root)
+
+  # Preorder traversal
+  $res = []
+  pre_order(root)
+  puts "\nPre-order traversal node sequence = #{$res}"
+
+  # Inorder traversal
+  $res.clear
+  in_order(root)
+  puts "\nIn-order traversal node sequence = #{$res}"
+
+  # Postorder traversal
+  $res.clear
+  post_order(root)
+  puts "\nPost-order traversal node sequence = #{$res}"
+end