#!/usr/bin/env python

coding: utf-8

In[1]:

class node:
def init(self, freq, symbol, left=None, right=None):
# frequency of symbol
self.freq = freq

	# symbol name (character)
	self.symbol = symbol

	# node left of current node
	self.left = left

	# node right of current node
	self.right = right

	# tree direction (0/1)
	self.huff = ''

utility function to print huffman

codes for all symbols in the newly

created Huffman tree

def printNodes(node, val=''):
# huffman code for current node
newVal = val + str(node.huff)

# if node is not an edge node
# then traverse inside it
if(node.left):
	printNodes(node.left, newVal)
if(node.right):
	printNodes(node.right, newVal)

	# if node is edge node then
	# display its huffman code
if(not node.left and not node.right):
	print(f"{node.symbol} -> {newVal}")

characters for huffman tree

chars = ['a', 'b', 'c', 'd', 'e', 'f']

frequency of characters

freq = [ 5, 9, 12, 13, 16, 45]

list containing unused nodes

nodes = []

converting characters and frequencies

into huffman tree nodes

for x in range(len(chars)):
nodes.append(node(freq[x], chars[x]))

while len(nodes) > 1:
# sort all the nodes in ascending order
# based on their frequency
nodes = sorted(nodes, key=lambda x: x.freq)

# pick 2 smallest nodes
left = nodes[0]
right = nodes[1]

# assign directional value to these nodes
left.huff = 0
right.huff = 1

# combine the 2 smallest nodes to create
# new node as their parent
newNode = node(left.freq+right.freq, left.symbol+right.symbol, left, right)
nodes.remove(left)
nodes.remove(right)
nodes.append(newNode)

Huffman Tree is ready!

printNodes(nodes[0])

DAA 2