Run length encoding
Quiz by GCSE Computer Science Teacher 2
GCSE (AQA)
Computer Science
English National Curriculum
Feel free to use or edit a copy
includes Teacher and Student dashboards
Measures 1 skill from
Measures 1 skill from
Track each student's skills and progress in your Mastery dashboards
With a free account, teachers can
- edit the questions
- save a copy for later
- start a class game
- automatically assign follow-up activities based on students’ scores
- assign as homework
- share a link with colleagues
- print as a bubble sheet
12 questions
Show answers
- Q1What is RLE (Run Length Encoding)?A count of the number of words in a programA searching algorithmThe length of time it takes an algorithm to runA compression algorithm30s3.3.8.c
- Q2Which of these is not an advantage of RLE?It is a lossless compression techniqueIt can be used on multiple file typesIt can greatly reduce the size of a file if there are enough patterns or 'runs' of dataIf there are not enough patterns it can result in a larger file size30s3.3.8.c
- Q3Which of these is not part of the RLE process of compressing documents?The letter and its number of occurrence is recorded in a pairPairs are stored in a binary treeThe occurrence of concurrent letters are recordedThe next letter is recorded once a new letter is reached30s3.3.8.c
- Q4What would the following set of letters be encoded as? 'aaabbbcccdddeefg'(a, b, c, d, 3) (e, 2) (f, g, 1)(a, 3) (b,3) (c, 3) (d, 3) (e, 2) (f, 1) (g, 1)(a)(b)(c)(d)3 (e)2 (f)g() 1(a, 3) (b,3) (c, 3) (d, 3) (e, 3) (f, 3) (g, 3)30s3.3.8.c
- Q5How many bits are needed for each 'run' of data?1682430s3.3.8.c
- Q6If the raw string 'aaabbbcccdddeeefg' uses 17 bytes, how many does the RLE version use?717141030s3.3.8.c
- Q7How does RLE compression work on images?It groups together pixels of similar sizesIt groups together all pixels of the same colour in the whole imageIt groups together pixels of the same colour that are next to each other in a runIt looks for similar shades of colours and makes them one shade30s3.3.8.c
- Q8What would the first line of this image look like after being compressed using RLE?0111003001 13 0102 1360s3.3.8.c
- Q9What would the second line of this image look like after being compressed using RLE?110112120010002 11 0260s3.3.8.c
- Q10Which row of the image is encoded as O2 Y1 O22nd5th1st3rd60s3.3.8.c
- Q11RLE compression is able to encode which of these data types or representations?PixelsStrings of multiple charactersSingle CharactersAll of these60s3.3.8.c
- Q12Why would the RLE compressed version of this use more storage than the original?There are only two colours in useRLE compressed images always use more spaceThere are too many similar coloursThere are not enough patterns60s3.3.8.c