Stream Parse and Aggregate Logs | Dataford Interview Questions

Problem

Given a list of log lines, implement a function that processes them in a single pass and returns aggregated counts per severity level. Each valid line has the format timestamp|event_id|severity|message, where severity is one of INFO, WARN, or ERROR. Ignore malformed lines, and count each event_id only once so duplicate records do not affect the result. Return a dictionary with keys INFO, WARN, ERROR, invalid, and duplicates.

Constraints

1 <= len(logs) <= 10^5
Each log line length is between 1 and 10^4
Valid severities are exactly INFO, WARN, and ERROR
event_id comparison is case-sensitive
The solution should run in linear time with respect to the total number of lines

Problem

Constraints

1 <= len(logs) <= 10^5
Each log line length is between 1 and 10^4
Valid severities are exactly INFO, WARN, and ERROR
event_id comparison is case-sensitive
The solution should run in linear time with respect to the total number of lines

Problem

Constraints

1 <= len(logs) <= 10^5
Each log line length is between 1 and 10^4
Valid severities are exactly INFO, WARN, and ERROR
event_id comparison is case-sensitive
The solution should run in linear time with respect to the total number of lines

Problem

Constraints

1 <= len(logs) <= 10^5
Each log line length is between 1 and 10^4
Valid severities are exactly INFO, WARN, and ERROR
event_id comparison is case-sensitive
The solution should run in linear time with respect to the total number of lines