Debug a Complex Issue | Dataford Interview Questions

How do you approach debugging a complex issue in your code?

Implement a focused debugging utility that compares an actual execution trace with an expected trace and identifies the first differing snapshot. Return -1 when both traces match exactly.

Use find_first_trace_mismatch(actual, expected), where each trace is a list of comparable snapshots, and return the zero-based mismatch index.

Constraints

0 <= actual.length, expected.length <= 10^5
Each snapshot is a comparable Python value
Return the smallest zero-based mismatch index
Return -1 only when the traces are identical

Function Signature

def find_first_trace_mismatch(actual, expected):

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