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_divide_and_conquer/build_tree.py

@@ -0,0 +1,54 @@
+"""
+File: build_tree.py
+Created Time: 2023-07-15
+Author: krahets (krahets@163.com)
+"""
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent.parent))
+from modules import TreeNode, print_tree
+
+
+def dfs(
+    preorder: list[int],
+    inorder_map: dict[int, int],
+    i: int,
+    l: int,
+    r: int,
+) -> TreeNode | None:
+    """Build binary tree: Divide and conquer"""
+    # Terminate when subtree interval is empty
+    if r - l < 0:
+        return None
+    # Initialize root node
+    root = TreeNode(preorder[i])
+    # Query m to divide left and right subtrees
+    m = inorder_map[preorder[i]]
+    # Subproblem: build left subtree
+    root.left = dfs(preorder, inorder_map, i + 1, l, m - 1)
+    # Subproblem: build right subtree
+    root.right = dfs(preorder, inorder_map, i + 1 + m - l, m + 1, r)
+    # Return root node
+    return root
+
+
+def build_tree(preorder: list[int], inorder: list[int]) -> TreeNode | None:
+    """Build binary tree"""
+    # Initialize hash table, storing in-order elements to indices mapping
+    inorder_map = {val: i for i, val in enumerate(inorder)}
+    root = dfs(preorder, inorder_map, 0, 0, len(inorder) - 1)
+    return root
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    preorder = [3, 9, 2, 1, 7]
+    inorder = [9, 3, 1, 2, 7]
+    print(f"Pre-order traversal = {preorder}")
+    print(f"In-order traversal = {inorder}")
+
+    root = build_tree(preorder, inorder)
+    print("The built binary tree is:")
+    print_tree(root)