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/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