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

* Add the intial translation of code of all the languages

* test

* revert

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* Add Python and Java code for EN version

en/codes/python/chapter_tree/array_binary_tree.py

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+"""
+File: array_binary_tree.py
+Created Time: 2023-07-19
+Author: krahets (krahets@163.com)
+"""
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent.parent))
+from modules import TreeNode, list_to_tree, print_tree
+
+
+class ArrayBinaryTree:
+    """Array-based binary tree class"""
+
+    def __init__(self, arr: list[int | None]):
+        """Constructor"""
+        self._tree = list(arr)
+
+    def size(self):
+        """List capacity"""
+        return len(self._tree)
+
+    def val(self, i: int) -> int | None:
+        """Get the value of the node at index i"""
+        # If the index is out of bounds, return None, representing a vacancy
+        if i < 0 or i >= self.size():
+            return None
+        return self._tree[i]
+
+    def left(self, i: int) -> int | None:
+        """Get the index of the left child of the node at index i"""
+        return 2 * i + 1
+
+    def right(self, i: int) -> int | None:
+        """Get the index of the right child of the node at index i"""
+        return 2 * i + 2
+
+    def parent(self, i: int) -> int | None:
+        """Get the index of the parent of the node at index i"""
+        return (i - 1) // 2
+
+    def level_order(self) -> list[int]:
+        """Level-order traversal"""
+        self.res = []
+        # Traverse array
+        for i in range(self.size()):
+            if self.val(i) is not None:
+                self.res.append(self.val(i))
+        return self.res
+
+    def dfs(self, i: int, order: str):
+        """Depth-first traversal"""
+        if self.val(i) is None:
+            return
+        # Pre-order traversal
+        if order == "pre":
+            self.res.append(self.val(i))
+        self.dfs(self.left(i), order)
+        # In-order traversal
+        if order == "in":
+            self.res.append(self.val(i))
+        self.dfs(self.right(i), order)
+        # Post-order traversal
+        if order == "post":
+            self.res.append(self.val(i))
+
+    def pre_order(self) -> list[int]:
+        """Pre-order traversal"""
+        self.res = []
+        self.dfs(0, order="pre")
+        return self.res
+
+    def in_order(self) -> list[int]:
+        """In-order traversal"""
+        self.res = []
+        self.dfs(0, order="in")
+        return self.res
+
+    def post_order(self) -> list[int]:
+        """Post-order traversal"""
+        self.res = []
+        self.dfs(0, order="post")
+        return self.res
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize binary tree
+    # Use a specific function to convert an array into a binary tree
+    arr = [1, 2, 3, 4, None, 6, 7, 8, 9, None, None, 12, None, None, 15]
+    root = list_to_tree(arr)
+    print("\nInitialize binary tree\n")
+    print("Array representation of the binary tree:")
+    print(arr)
+    print("Linked list representation of the binary tree:")
+    print_tree(root)
+
+    # Array-based binary tree class
+    abt = ArrayBinaryTree(arr)
+
+    # Access node
+    i = 1
+    l, r, p = abt.left(i), abt.right(i), abt.parent(i)
+    print(f"\nCurrent node index is {i}, value is {abt.val(i)}")
+    print(f"Its left child node index is {l}, value is {abt.val(l)}")
+    print(f"Its right child node index is {r}, value is {abt.val(r)}")
+    print(f"Its parent node index is {p}, value is {abt.val(p)}")
+
+    # Traverse tree
+    res = abt.level_order()
+    print("\nLevel-order traversal is:", res)
+    res = abt.pre_order()
+    print("Pre-order traversal is:", res)
+    res = abt.in_order()
+    print("In-order traversal is:", res)
+    res = abt.post_order()
+    print("Post-order traversal is:", res)

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))

en/codes/python/chapter_tree/binary_search_tree.py

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+"""
+File: binary_search_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 BinarySearchTree:
+    """Binary search tree"""
+
+    def __init__(self):
+        """Constructor"""
+        # Initialize empty tree
+        self._root = None
+
+    def get_root(self) -> TreeNode | None:
+        """Get binary tree root node"""
+        return self._root
+
+    def search(self, num: 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 < num:
+                cur = cur.right
+            # Target node is in cur's left subtree
+            elif cur.val > num:
+                cur = cur.left
+            # Found target node, break loop
+            else:
+                break
+        return cur
+
+    def insert(self, num: int):
+        """Insert node"""
+        # If tree is empty, initialize root node
+        if self._root is None:
+            self._root = TreeNode(num)
+            return
+        # Loop find, break after passing leaf nodes
+        cur, pre = self._root, None
+        while cur is not None:
+            # Found duplicate node, thus return
+            if cur.val == num:
+                return
+            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
+        # Insert node
+        node = TreeNode(num)
+        if pre.val < num:
+            pre.right = node
+        else:
+            pre.left = node
+
+    def remove(self, num: int):
+        """Remove node"""
+        # If tree is empty, return
+        if self._root is None:
+            return
+        # Loop find, break after passing leaf nodes
+        cur, pre = self._root, None
+        while cur is not None:
+            # Found node to be removed, break loop
+            if cur.val == num:
+                break
+            pre = cur
+            # Node to be removed is in cur's right subtree
+            if cur.val < num:
+                cur = cur.right
+            # Node to be removed is in cur's left subtree
+            else:
+                cur = cur.left
+        # If no node to be removed, return
+        if cur is None:
+            return
+
+        # Number of child nodes = 0 or 1
+        if cur.left is None or cur.right is None:
+            # When the number of child nodes = 0/1, child = null/that child node
+            child = cur.left or cur.right
+            # Remove node cur
+            if cur != self._root:
+                if pre.left == cur:
+                    pre.left = child
+                else:
+                    pre.right = child
+            else:
+                # If the removed node is the root, reassign the root
+                self._root = child
+        # Number of child nodes = 2
+        else:
+            # Get the next node in in-order traversal of cur
+            tmp: TreeNode = cur.right
+            while tmp.left is not None:
+                tmp = tmp.left
+            # Recursively remove node tmp
+            self.remove(tmp.val)
+            # Replace cur with tmp
+            cur.val = tmp.val
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize binary search tree
+    bst = BinarySearchTree()
+    nums = [8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15]
+    # Note that different insertion orders can result in various tree structures. This particular sequence creates a perfect binary tree
+    for num in nums:
+        bst.insert(num)
+    print("\nInitialized binary tree is\n")
+    print_tree(bst.get_root())
+
+    # Search node
+    node = bst.search(7)
+    print("\nFound node object is: {}, node value = {}".format(node, node.val))
+
+    # Insert node
+    bst.insert(16)
+    print("\nAfter inserting node 16, the binary tree is\n")
+    print_tree(bst.get_root())
+
+    # Remove node
+    bst.remove(1)
+    print("\nAfter removing node 1, the binary tree is\n")
+    print_tree(bst.get_root())
+
+    bst.remove(2)
+    print("\nAfter removing node 2, the binary tree is\n")
+    print_tree(bst.get_root())
+
+    bst.remove(4)
+    print("\nAfter removing node 4, the binary tree is\n")
+    print_tree(bst.get_root())

en/codes/python/chapter_tree/binary_tree.py

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+"""
+File: binary_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
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize binary tree
+    # Initialize node
+    n1 = TreeNode(val=1)
+    n2 = TreeNode(val=2)
+    n3 = TreeNode(val=3)
+    n4 = TreeNode(val=4)
+    n5 = TreeNode(val=5)
+    # Construct node references (pointers)
+    n1.left = n2
+    n1.right = n3
+    n2.left = n4
+    n2.right = n5
+    print("\nInitialize binary tree\n")
+    print_tree(n1)
+
+    # Insert and remove nodes
+    P = TreeNode(0)
+    # Insert node P between n1 -> n2
+    n1.left = P
+    P.left = n2
+    print("\nAfter inserting node P\n")
+    print_tree(n1)
+    # Remove node
+    n1.left = n2
+    print("\nAfter removing node P\n")
+    print_tree(n1)

en/codes/python/chapter_tree/binary_tree_bfs.py

@@ -0,0 +1,42 @@
+"""
+File: binary_tree_bfs.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, list_to_tree, print_tree
+from collections import deque
+
+
+def level_order(root: TreeNode | None) -> list[int]:
+    """Level-order traversal"""
+    # Initialize queue, add root node
+    queue: deque[TreeNode] = deque()
+    queue.append(root)
+    # Initialize a list to store the traversal sequence
+    res = []
+    while queue:
+        node: TreeNode = queue.popleft()  # Queue dequeues
+        res.append(node.val)  # Save node value
+        if node.left is not None:
+            queue.append(node.left)  # Left child node enqueues
+        if node.right is not None:
+            queue.append(node.right)  # Right child node enqueues
+    return res
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize binary tree
+    # Use a specific function to convert an array into a binary tree
+    root: TreeNode = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
+    print("\nInitialize binary tree\n")
+    print_tree(root)
+
+    # Level-order traversal
+    res: list[int] = level_order(root)
+    print("\nPrint sequence of nodes from level-order traversal = ", res)

en/codes/python/chapter_tree/binary_tree_dfs.py

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+"""
+File: binary_tree_dfs.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, list_to_tree, print_tree
+
+
+def pre_order(root: TreeNode | None):
+    """Pre-order traversal"""
+    if root is None:
+        return
+    # Visit priority: root node -> left subtree -> right subtree
+    res.append(root.val)
+    pre_order(root=root.left)
+    pre_order(root=root.right)
+
+
+def in_order(root: TreeNode | None):
+    """In-order traversal"""
+    if root is None:
+        return
+    # Visit priority: left subtree -> root node -> right subtree
+    in_order(root=root.left)
+    res.append(root.val)
+    in_order(root=root.right)
+
+
+def post_order(root: TreeNode | None):
+    """Post-order traversal"""
+    if root is None:
+        return
+    # Visit priority: left subtree -> right subtree -> root node
+    post_order(root=root.left)
+    post_order(root=root.right)
+    res.append(root.val)
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize binary tree
+    # Use a specific function to convert an array into a binary tree
+    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
+    print("\nInitialize binary tree\n")
+    print_tree(root)
+
+    # Pre-order traversal
+    res = []
+    pre_order(root)
+    print("\nPrint sequence of nodes from pre-order traversal = ", res)
+
+    # In-order traversal
+    res.clear()
+    in_order(root)
+    print("\nPrint sequence of nodes from in-order traversal = ", res)
+
+    # Post-order traversal
+    res.clear()
+    post_order(root)
+    print("\nPrint sequence of nodes from post-order traversal = ", res)