ITPEC IP April 2024 Question 25
ITPEC IP April 2024 — Question 25 of 100
The compressed representation has 13 characters, so the compression ratio is 52.0%. The calculation is 13 ÷ 25 × 100 = 52.0%. Scan all 25 pixels continuously from left to right and top to bottom. Runs can cross a row boundary, as demonstrated in Fig. 1.
The color runs in Fig. 2 have lengths B6, W4, B4, W1, B1, W4, B1, W4. A run of two or more uses two characters: its color and its count. A single pixel uses one character. The encoded length is therefore 2 + 2 + 2 + 1 + 1 + 2 + 1 + 2 = 13. Dividing by the original 25 characters gives 52.0%.
Answer (b)
Why not others: (a), (c), and (d) do not equal the encoded-to-original length ratio 13/25. They result from miscounting runs or reversing the ratio.
Key rule: In run-length encoding, first determine maximal consecutive runs across the entire scan sequence, then count the characters required for each run.
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