84. AQA GCSE (8525) SLR13 – 3.3 Compression Huffman coding

What is Huffman coding?

• A lossy compression method

• A lossless compression method

• A programming language

• A type of encryption algorithm

Answer explanation

Huffman coding is a lossless compression method that efficiently encodes data by assigning shorter codes to more frequent characters.

What is often compressed using Huffman coding?

• Video files

• Audio files

• Text documents

• Executable files

Answer explanation

Huffman coding is often used to compress text documents efficiently, making them the correct choice in this case.

How many characters does the phrase 'Peter Piper picked a pepper' contain, including spaces?

• 26

• 27

• 25

• 28

Answer explanation

The phrase 'Peter Piper picked a pepper' contains 27 characters, including spaces. Therefore, the correct answer is 27.

How many times does the letter 'P' appear in the phrase used in the example?

• 7

• 6

• 5

• 8

Answer explanation

The letter 'P' appears 7 times in the phrase used in the example, so the correct answer is 7.

What data structure does Huffman coding make use of?

• Linked lists

• Binary trees

• Arrays

• Graphs

Answer explanation

Huffman coding makes use of binary trees to efficiently encode data by assigning shorter codes to more frequent characters.

How many child nodes can each node in a binary tree have?

• One

• Three

• No limit

• Two

Answer explanation

Each node in a binary tree can have at most two child nodes, making the correct answer 'Two'.

In Huffman coding, where do characters that occur more frequently appear in the tree?

• Outside the tree

• Towards the top

• Towards the bottom

• Randomly placed

Answer explanation

In Huffman coding, characters that occur more frequently appear towards the top of the tree as they are assigned shorter codes, optimizing the encoding process.

What is required to interpret from a Huffman tree for the exam?

• Creating a Huffman tree

• Calculating the tree's height

• Coloring the Huffman tree

• Calculating bits for data compression

Answer explanation

Calculating bits for data compression is required to interpret from a Huffman tree for the exam.

How is the character 'P' encoded using the Huffman tree in the example?

• 1 1

• 1 0

• 0 1

• 0 0

Answer explanation

The character 'P' is encoded as 1 0 in the Huffman tree example, where 'P' is represented by 1 and the path to reach 'P' is 0.

How many bits are used to encode the character 'A'?

• Five

• Three

• Four

• Two

Answer explanation

The correct answer is 'Four' because the character 'A' is encoded using 4 bits in ASCII encoding.