Add Mirror a Binary Tree solution

data_structures/binary_tree/invert_binary_tree.py

@@ -0,0 +1,76 @@
+"""
+Given the root of a binary tree, invert the tree, and return its root.
+
+Leetcode problem reference: https://leetcode.com/problems/invert-binary-tree/
+"""
+
+from __future__ import annotations
+
+
+class Node:
+    """
+    A Node has value variable and pointers to Nodes to its left and right.
+    """
+
+    def __init__(self, value: int) -> None:
+        self.value = value
+        self.left: Node | None = None
+        self.right: Node | None = None
+
+
+def display(tree: Node | None) -> None:  
+    """
+    Prints the inorder traversal of a tree
+    """
+    if tree:
+        display(tree.left)
+        print(tree.value, end=" ")
+        display(tree.right)
+
+def invert_binary_tree(root: Node| None) -> None:
+    """
+    Inverts a binary tree and returns the root node of the binary tree
+    """
+    if root != None: #If root is not None
+            temp : Node = root.left  #Save left Node in a temp variable
+            # Swap the Nodes
+            root.left = root.right 
+            root.right = temp
+            # Now, invoke the function recursively for both the children
+            invert_binary_tree(root.left) 
+            invert_binary_tree(root.right)
+    # Return the Node
+    return root
+
+if __name__ == "__main__":
+    # Create a binary tree with 7 Nodes
+    t1 : Node = Node(1)
+    t1.left = Node(2)
+    t1.right = Node(3)
+    t1.left.left = Node(4)
+    t1.left.right = Node(5)
+    t1.right.left = Node(6)
+    t1.right.right = Node(7)
+
+    """
+     The tree is like
+              1
+        2         3
+      4   5     6    7
+    """
+
+    print("Tree: ",end=" ")
+    display(t1)  
+
+    #Invert the binary tree (t1) and store the returned Node in t2
+    t2 : Node = invert_binary_tree(t1)  
+    """
+     The inverted tree is like
+             1
+        3         2
+      7    6    5   4     
+    """
+
+    print("\nInverted Tree: ", end=" ")
+    display(t2)  
+    print()