Added functionality to calculate the diameter of given binary tree

data_structures/binary_tree/diameter_of_binary_tree.py

@@ -0,0 +1,73 @@
+''' 
+The diameter/width of a tree is defined as the number of nodes on the longest path between two end nodes. 
+'''
+
+# A binary tree Node
+
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.left = None
+        self.right = None
+
+# utility class to pass height object
+class Height:
+	def __init__(self):
+		self.h = 0
+
+
+# Function to calculate diameter of the given binary tree
+def calculate_diameter(root:Node, height:int) -> int:
+
+	# to store height of left and right subtree
+	lh = Height()
+	rh = Height()
+
+	# base condition- when binary tree is empty
+	if root is None:
+		height.h = 0
+		return 0
+
+	# ldiameter --> diameter of left subtree
+	# rdiameter --> diameter of right subtree
+
+	# height of left subtree and right subtree is obtained from lh and rh and returned value of function is stored in ldiameter and rdiameter
+
+	ldiameter = calculate_diameter(root.left, lh)
+	rdiameter = calculate_diameter(root.right, rh)
+
+	# height of tree will be max of left subtree
+	# height and right subtree height plus1
+
+	height.h = max(lh.h, rh.h) + 1
+
+	# return maximum of the following
+	# 1)left diameter
+	# 2)right diameter
+	# 3)left height + right height + 1
+	return max(lh.h + rh.h + 1, max(ldiameter, rdiameter))
+
+
+def diameter(root:Node) -> int:
+	height = Height()
+	return calculate_diameter(root, height)
+
+
+if __name__ == "__main__":
+	root = Node(1)
+	root.left = Node(2)
+	root.right = Node(3)
+	root.left.left = Node(4)
+	root.left.right = Node(5)
+
+	"""
+Constructed binary tree is 
+		1
+	   / \
+	  2	  3
+	 / \
+	4	 5
+"""
+
+	print("The diameter of the binary tree is:", end=" ")
+	print(diameter(root))