How should I practice DMA Stream Distribution?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Etched phone screen problems in FastPrep.

Is DMA Stream Distribution associated with Etched?

FastPrep tags this as a Etched phone screen coding practice problem when the problem catalog has that company and stage context.

DMA Stream Distribution

Etched● MediumFULLTIMEPHONE SCREEN

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Problem statement

A DMA controller receives ordered write streams and fills ordered memory regions. Stream i contains streamBytes[i] bytes, and region j has regionCapacities[j] available bytes.

Consume each stream fully before moving to the next stream, and fill each region before moving to the next region. A stream may span regions and a region may contain bytes from several streams. Return one row [streamIndex, regionIndex, bytesMoved] for every non-empty transfer. Total region capacity is sufficient for all streams.

Function

distributeDmaStreams(streamBytes: int[], regionCapacities: int[]) → int[][]

Examples

Example 1

streamBytes = [8,4]regionCapacities = [5,5,2]return = [[0,0,5],[0,1,3],[1,1,2],[1,2,2]]

The first stream fills region 0 and uses three bytes of region 1; the second finishes region 1 and fills region 2.

Example 2

streamBytes = [3,2]regionCapacities = [10]return = [[0,0,3],[1,0,2]]

Both streams fit sequentially in the same region.

Constraints

0 <= streamBytes.length, regionCapacities.length <= 100000
Every byte count and capacity is positive.
Total region capacity is at least total stream bytes.