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Data compression

Data compression

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Question 8

Select one option to show what code should be written at point P5 of the algorithm in Figure 1 to correctly implement run-length encoding.

Figure 1

sequence ← USERINPUT
compressed ← ""
count ← 1
i ← 0
WHILE i < LEN(sequence) - 1
    IF sequence[i] = sequence[i + 1] THEN
        count ← count + 1
    ELSE
        compressed ← compressed + TO_STRING(count) + sequence[i]
        count ← 1
    ENDIF
    P5
ENDWHILE
compressed ← compressed + TO_STRING(count) + sequence[LEN(sequence) - 1]
OUTPUT compressed
A

i←i−1i \leftarrow i - 1i←i−1

B

i←i+1i \leftarrow i + 1i←i+1

C

i←i+2i \leftarrow i + 2i←i+2

D

i←count+1i \leftarrow \text{count} + 1i←count+1

Markscheme

Data compression Questions

  1. GCSE
  2. /Computer Science
  3. /Data compression

37 exam-style questions on AQA GCSE Computer Science Data compression. Each one has a worked solution and a mark scheme showing where the marks go.

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