Dynamic Programming / 2Dhard70 minDevOps / SRE Engineer

OnCall Grid Reliability DP

DevOps / SRE Engineer signal: grid DP + path optimization in a on-call routing context. This is a ProdMatch-owned devops sre drill, framed as a March 2026 Atlassian Incident Response simulation, not a copied platform question.

Company context

Atlassian · Incident Response

Freshness

March 2026

Product surface

on-call routing

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

Question

Model on-call routing 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

blast-radius graphs
alert dedupe
rolling windows
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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