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Representing algorithms

Representing algorithms

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Question 21

An algorithm is designed to perform Run-Length Encoding (RLE) on an input string of characters.

The pseudocode contains several missing parts, represented by the labels L1 to L5.

data ← L1
index ← 0
run_length ← L2
WHILE index < LEN(data) - 1
    IF data[index] = data[index + 1] THEN
        run_length ← run_length + 1
    ELSE
        OUTPUT run_length
        OUTPUT data[index]
        run_length ← L4
    ENDIF
    index ← L5
ENDWHILE
OUTPUT run_length
OUTPUT data[index]

What value should be written at point L2 of the algorithm to ensure the sequence matches are counted correctly?

A

−1-1−1

B

000

C

111

D

222

Markscheme

Representing algorithms Questions

  1. GCSE
  2. /Computer Science
  3. /Representing algorithms

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

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