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Fix node balancing

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This commit is contained in:
Matthew Grove
2020-02-27 08:46:53 +00:00
parent 782bfe42f5
commit 5b628e0f9b
1 changed files with 20 additions and 5 deletions
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25
huffman-coding.py
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@@ -37,6 +37,10 @@ def encode(txt):
new_node = (nodes[0], nodes[1]) new_node = (nodes[0], nodes[1])
# combine two least frequent characters' frequencies into a total frequency, to be used at the top level of the list of nodes # combine two least frequent characters' frequencies into a total frequency, to be used at the top level of the list of nodes
new_frequency = frequencies[0] + frequencies[1] new_frequency = frequencies[0] + frequencies[1]
print(f"New node: {new_node}, new frequency: {new_frequency}")
print(f"Nodes to be removed: {nodes[0:2]}, frequencies to be removed: {frequencies[0:2]}")
# remove nodes that have been nested inside the new node # remove nodes that have been nested inside the new node
del nodes[0:2] del nodes[0:2]
# remove frequencies that have been summed and added to the new frequency # remove frequencies that have been summed and added to the new frequency
@@ -46,11 +50,13 @@ def encode(txt):
# if the largest frequency is smaller than the new one, place the new node at the end of the list # if the largest frequency is smaller than the new one, place the new node at the end of the list
if (frequencies[-1] < new_frequency): if (frequencies[-1] < new_frequency):
i = -1 print("i = -1")
i = len(frequencies)
else: else:
# loop over every frequency # loop over every frequency
for index, frequency in enumerate(frequencies): for index, frequency in enumerate(frequencies):
if (frequency >= new_frequency): if (frequency >= new_frequency):
print(f"{frequency} >= {new_frequency}. Breaking. Index is {index}")
# record the index to insert the frequency at # record the index to insert the frequency at
i = index i = index
break break
@@ -58,18 +64,27 @@ def encode(txt):
# insert the new node and frequency in their rightful positions, maintaining ascending order of frequency # insert the new node and frequency in their rightful positions, maintaining ascending order of frequency
nodes.insert(i, new_node) nodes.insert(i, new_node)
frequencies.insert(i, new_frequency) frequencies.insert(i, new_frequency)
print(f"Nodes: {nodes}, frequencies: {frequencies}")
print(f"Nodes: {nodes}") print(f"Nodes: {nodes}")
# encrypted text # encrypted text
output = "" output = ""
# characters and encoded values
encoded_values = {}
for char in set(txt):
# find the character's path and add it to the dictionary
encoded_values[char] = "".join(find_node(nodes, char))
print(f"Encoded values: {encoded_values}")
for char in txt: for char in txt:
# find its path and add it to the encrypted text # add text to final output
output += "".join(find_node(nodes, char)) output += encoded_values[char]
print(f"Encoded message: {output}") print(f"Encoded message: {output}")
return [output, nodes] return [output, nodes]
def decode(txt, nodes): def decode(txt, nodes):
@@ -90,4 +105,4 @@ def decode(txt, nodes):
return output return output
encoding = encode(input("Text: ")) encoding = encode(input("Text: "))
decode(encoding[0], encoding[1]) decode(encoding[0], encoding[1])