Dynamic Programming / 2Dhard70 minData Engineer

Metrics Grid Reliability DP

Data Engineer signal: grid DP + path optimization in a metric dependency graph context. This is a ProdMatch-owned data engineer drill, framed as a May 2026 Apple Analytics Platform simulation, not a copied platform question.

Company context

Apple · Analytics Platform

Freshness

May 2026

Product surface

metric dependency graph

ProdMatch interview simulation based on product-team patterns; not a claim of a real company question.

Question

Model metric dependency graph as a grid of processing zones. Move only right or down. Return the maximum reliability path score while avoiding blocked cells.

Input

Grid of scores with blocked cells marked -1.

Output

Maximum score from top-left to bottom-right, or -1.

Constraints

1 <= rows, cols <= 1000
Scores may be zero.
Start or end may be blocked.

Concepts

stream windows
watermarks
lineage DAGs
grid DP
path optimization
obstacle handling

[[5,1],[2,4]] -> 11

Approach

Try framing your own approach first. The 30 seconds you think before peeking is where learning happens.

Clean Solution

Reveal the approach first.

How well did you understand?

Your rating tunes when this problem shows up again.

Common Mistakes

Blocked start/end must be handled before the loop.
Use the impossible sentinel consistently.

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