translation: Add Python and Java code for EN version (#1345)

* Add the intial translation of code of all the languages

* test

* revert

* Remove

* Add Python and Java code for EN version

en/codes/python/chapter_tree/avl_tree.py

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+"""
+File: avl_tree.py
+Created Time: 2022-12-20
+Author: a16su (lpluls001@gmail.com)
+"""
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent.parent))
+from modules import TreeNode, print_tree
+
+
+class AVLTree:
+    """AVL tree"""
+
+    def __init__(self):
+        """Constructor"""
+        self._root = None
+
+    def get_root(self) -> TreeNode | None:
+        """Get binary tree root node"""
+        return self._root
+
+    def height(self, node: TreeNode | None) -> int:
+        """Get node height"""
+        # Empty node height is -1, leaf node height is 0
+        if node is not None:
+            return node.height
+        return -1
+
+    def update_height(self, node: TreeNode | None):
+        """Update node height"""
+        # Node height equals the height of the tallest subtree + 1
+        node.height = max([self.height(node.left), self.height(node.right)]) + 1
+
+    def balance_factor(self, node: TreeNode | None) -> int:
+        """Get balance factor"""
+        # Empty node balance factor is 0
+        if node is None:
+            return 0
+        # Node balance factor = left subtree height - right subtree height
+        return self.height(node.left) - self.height(node.right)
+
+    def right_rotate(self, node: TreeNode | None) -> TreeNode | None:
+        """Right rotation operation"""
+        child = node.left
+        grand_child = child.right
+        # Rotate node to the right around child
+        child.right = node
+        node.left = grand_child
+        # Update node height
+        self.update_height(node)
+        self.update_height(child)
+        # Return the root of the subtree after rotation
+        return child
+
+    def left_rotate(self, node: TreeNode | None) -> TreeNode | None:
+        """Left rotation operation"""
+        child = node.right
+        grand_child = child.left
+        # Rotate node to the left around child
+        child.left = node
+        node.right = grand_child
+        # Update node height
+        self.update_height(node)
+        self.update_height(child)
+        # Return the root of the subtree after rotation
+        return child
+
+    def rotate(self, node: TreeNode | None) -> TreeNode | None:
+        """Perform rotation operation to restore balance to the subtree"""
+        # Get the balance factor of node
+        balance_factor = self.balance_factor(node)
+        # Left-leaning tree
+        if balance_factor > 1:
+            if self.balance_factor(node.left) >= 0:
+                # Right rotation
+                return self.right_rotate(node)
+            else:
+                # First left rotation then right rotation
+                node.left = self.left_rotate(node.left)
+                return self.right_rotate(node)
+        # Right-leaning tree
+        elif balance_factor < -1:
+            if self.balance_factor(node.right) <= 0:
+                # Left rotation
+                return self.left_rotate(node)
+            else:
+                # First right rotation then left rotation
+                node.right = self.right_rotate(node.right)
+                return self.left_rotate(node)
+        # Balanced tree, no rotation needed, return
+        return node
+
+    def insert(self, val):
+        """Insert node"""
+        self._root = self.insert_helper(self._root, val)
+
+    def insert_helper(self, node: TreeNode | None, val: int) -> TreeNode:
+        """Recursively insert node (helper method)"""
+        if node is None:
+            return TreeNode(val)
+        # 1. Find insertion position and insert node
+        if val < node.val:
+            node.left = self.insert_helper(node.left, val)
+        elif val > node.val:
+            node.right = self.insert_helper(node.right, val)
+        else:
+            # Do not insert duplicate nodes, return
+            return node
+        # Update node height
+        self.update_height(node)
+        # 2. Perform rotation operation to restore balance to the subtree
+        return self.rotate(node)
+
+    def remove(self, val: int):
+        """Remove node"""
+        self._root = self.remove_helper(self._root, val)
+
+    def remove_helper(self, node: TreeNode | None, val: int) -> TreeNode | None:
+        """Recursively remove node (helper method)"""
+        if node is None:
+            return None
+        # 1. Find and remove the node
+        if val < node.val:
+            node.left = self.remove_helper(node.left, val)
+        elif val > node.val:
+            node.right = self.remove_helper(node.right, val)
+        else:
+            if node.left is None or node.right is None:
+                child = node.left or node.right
+                # Number of child nodes = 0, remove node and return
+                if child is None:
+                    return None
+                # Number of child nodes = 1, remove node
+                else:
+                    node = child
+            else:
+                # Number of child nodes = 2, remove the next node in in-order traversal and replace the current node with it
+                temp = node.right
+                while temp.left is not None:
+                    temp = temp.left
+                node.right = self.remove_helper(node.right, temp.val)
+                node.val = temp.val
+        # Update node height
+        self.update_height(node)
+        # 2. Perform rotation operation to restore balance to the subtree
+        return self.rotate(node)
+
+    def search(self, val: int) -> TreeNode | None:
+        """Search node"""
+        cur = self._root
+        # Loop find, break after passing leaf nodes
+        while cur is not None:
+            # Target node is in cur's right subtree
+            if cur.val < val:
+                cur = cur.right
+            # Target node is in cur's left subtree
+            elif cur.val > val:
+                cur = cur.left
+            # Found target node, break loop
+            else:
+                break
+        # Return target node
+        return cur
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+
+    def test_insert(tree: AVLTree, val: int):
+        tree.insert(val)
+        print("\nInsert node {} after, AVL tree is".format(val))
+        print_tree(tree.get_root())
+
+    def test_remove(tree: AVLTree, val: int):
+        tree.remove(val)
+        print("\nRemove node {} after, AVL tree is".format(val))
+        print_tree(tree.get_root())
+
+    # Initialize empty AVL tree
+    avl_tree = AVLTree()
+
+    # Insert node
+    # Notice how the AVL tree maintains balance after inserting nodes
+    for val in [1, 2, 3, 4, 5, 8, 7, 9, 10, 6]:
+        test_insert(avl_tree, val)
+
+    # Insert duplicate node
+    test_insert(avl_tree, 7)
+
+    # Remove node
+    # Notice how the AVL tree maintains balance after removing nodes
+    test_remove(avl_tree, 8)  # Remove node with degree 0
+    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)
+    print("\nFound node object is {}, node value = {}".format(result_node, result_node.val))