Debug a Simulated Production Failure | Dataford Interview Questions

Debug a piece of code that simulates a common production failure.

The failure is a cascading dependency failure. Given a directed dependency graph and an initial set of failed services, return every service that becomes unavailable because it directly or transitively depends on a failed service. Include the initially failed services and return names in lexicographic order.

Input and Output

dependencies is a dictionary mapping each service to its direct dependencies. initial_failures is a list of failed service names. Return a list of all failed services.

Constraints

1 <= number of services <= 1000
Each service name is a non-empty string
Each dependency name appears as a key or as a dependency value
A service may list the same dependency more than once
The dependency graph may contain cycles
initial_failures contains valid service names

Function Signature

def cascading_failures(dependencies, initial_failures):

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