AP CSA FRQ Guide
2011 FRQ 1: Sound
Limit sample amplitudes to a maximum absolute value and return a new array with leading silence removed.
Array Processing22 minute targetarraysmutationMath.abscopying
Skills Tested
What this FRQ is really practicing
arraysmutationMath.abscopying
Treat these skills as the study checklist. If any tag feels shaky, review that topic before attempting the full written response.
Starter Approach
How to begin without copying a solution
- 1Mutate samples whose absolute value exceeds the limit and count changes.
- 2Find the first nonzero sample and copy the remaining samples into a new array.
Write a first attempt before revealing any solution outline. Most AP CSA FRQ progress comes from tracing your own code and finding the missing case.
Common Mistakes
Mistakes to watch for while writing
Clamping only positive samples.
Returning the limit instead of the number of changes.
Removing all zeros instead of only leading silence.
Self Check
Review questions before you submit
Checks absolute amplitude against the limit.
Both positive and negative samples can exceed the limit.
Clamps large positive and negative values correctly.
Positive values become limit and negative values become -limit.
Counts how many samples were changed.
Return the number of mutated entries.
Creates a new array after leading zeros.
Do not just shift values inside the original array.
Practice Links