Find Frequent Error Sequences | Dataford Interview Questions

Astra logs contain timestamped error codes generated by platform components. Given a list of log events and a sequence length k, return the most frequent contiguous sequence of k error codes after ordering events chronologically.

Each event is represented as [timestamp, error_code], where timestamp is a unique integer and error_code is a string. Count overlapping sequences. If multiple sequences have the same highest frequency, return the lexicographically smallest sequence. Return an empty list when fewer than k events are provided.

Formal Specification

Implement most_frequent_error_sequence(logs, k).

Input: logs, a list of [int, str] pairs, and positive integer k
Output: a list of k error-code strings representing the selected sequence
Timestamps may be unsorted in the input, but are unique
The input list must not be modified

Constraints

0 <= len(logs) <= 100000
1 <= k <= len(logs) when logs is non-empty
Each event has the form [timestamp, error_code]
Timestamps are unique integers
Error codes are non-empty strings

Function Signature

def most_frequent_error_sequence(logs, k):

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