Debugging an Issue | Dataford Interview Questions

Explain how to debug an issue.

For this coding exercise, implement a trace checker that helps isolate the first incorrect execution step. Given operations and their reported states, simulate the state from zero and return the first index where the report differs from the simulation, or -1 if the trace is consistent.

Input: a list of dictionaries with op, amount, and reported; op is inc, dec, or set. Output: an integer index.

Constraints

1 <= len(trace) <= 500
Each operation is one of inc, dec, or set
Amounts and reported states are integers
The initial state is 0
Return the smallest invalid index, or -1 when every step is valid

Function Signature

def debug_issue(trace):

Your question is Debugging an Issue. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Explain how to debug an issue.

Input: a list of dictionaries with op, amount, and reported; op is inc, dec, or set. Output: an integer index.

Constraints

1 <= len(trace) <= 500
Each operation is one of inc, dec, or set
Amounts and reported states are integers
The initial state is 0
Return the smallest invalid index, or -1 when every step is valid

Function Signature

def debug_issue(trace):

Your question is Debugging an Issue. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.