How should I practice Parse and Order Structured Logs?

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Problem · Array

Parse and Order Structured Logs

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CoinbaseFULLTIMEONSITE INTERVIEW

Problem statement

Parse an array of structured log lines. A valid line has exactly four pipe-separated fields:

timestamp|level|service|message

timestamp is a canonical nonnegative decimal integer: it is 0 or begins with a digit from 1 through 9, and its value is at most 1000000000.
level is exactly INFO, WARN, or ERROR.
service is nonempty and contains only English letters, digits, underscores, or hyphens.
message is nonempty. No field contains the pipe character.

Ignore every invalid line. For each valid line, return one row [timestamp, level, service, message]. Sort the returned rows by numeric timestamp in ascending order. When timestamps are equal, preserve the original input order.

Function

parseLogs(logs: String[]) → String[][]

Examples

Example 1

logs = ["10|INFO|api|started","2|ERROR|db|down","10|WARN|api|slow"]return = [["2","ERROR","db","down"],["10","INFO","api","started"],["10","WARN","api","slow"]]

The timestamp 2 comes first. The two timestamp-10 rows retain their input order.

Example 2

logs = ["01|INFO|api|leading zero","0|INFO|boot_service|ready now","7|DEBUG|api|trace","8|WARN|api|","9|ERROR|db|disk full"]return = [["0","INFO","boot_service","ready now"],["9","ERROR","db","disk full"]]

The leading-zero timestamp, unsupported level, and empty message are invalid and ignored.

Constraints

0 <= logs.length <= 100000.
1 <= logs[i].length <= 500.
Every input character is printable ASCII.