diameter of BTree (#355)

Co-authored-by: 1334monika <monkaasahu1@gmail.com>

Python/diameterBineryTree.py

@@ -0,0 +1,33 @@
+#Function to find the diameter of the   given   binary tree.
+
+
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+class Solution:
+    def diameterOfBinaryTree(self, root: TreeNode) -> int:
+        # Initialize the diameter
+        self.diameter = 0
+
+        def depth(node: TreeNode) -> int:
+            # If the node is None, return 0 (base case for leaf nodes)
+            if not node:
+                return 0
+
+            # Recursively find the depth of the left and right subtree
+            left_depth = depth(node.left)
+            right_depth = depth(node.right)
+
+            # The diameter at this node is the sum of the left depth and right depth
+            self.diameter = max(self.diameter, left_depth + right_depth)
+
+            # Return the height of the current node
+            return max(left_depth, right_depth) + 1
+
+        # Start the depth-first search from the root
+        depth(root)
+
+        return self.diameter