Find the Five Busiest Client IPs in Request Logs

During an API traffic incident, find the five client IP addresses with the most completed request-log entries across several files. Ignore background-service messages and auxiliary messages that mention an IP without recording a request.

Implement top_request_ips(files: string[][]) -> string[][]. Each inner input array contains the lines of one file. Return rows [ip,count], ordered by descending numeric count and then by ascending numeric IPv4 address. Return fewer than five rows if fewer than five distinct client addresses occur.

Constraints & Assumptions

The source provides file logs with HTTP request lines, background messages, and a separate Client IP= redirect diagnostic. Passing file contents directly and the deterministic tie order are explicit practice choices.

• At most 20 files and 200000 lines in total; total input length is at most 20000000 characters.
• A counted line contains a request portion of the form METHOD URL HTTP/version, followed later on that same line by from A.B.C.D:port - status. METHOD is one of GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS. Version is 1.0, 1.1, or 2.0. Status is exactly three decimal digits.
• Request-line quote characters may be escaped with backslashes, as in the reported logs. Match the request and client-address fields, not an assumed fixed quote position.
• Counted lines have exactly one such request/client pair. Other lines have no complete pair, even if they contain Client IP= or an isolated from substring.
• IPv4 octets are decimal integers from 0 to 255 with no leading zeroes except 0; ports are decimal integers from 1 to 65535. IPv6, forwarded-header interpretation, multiline records, and malformed request fields are outside this practice contract.
• Count every completed request line once, including non-2xx statuses, repeated request IDs if any, private IPs, and lines in different files. Ignore the port when grouping. No file-overlap deduplication is implied.
• Return counts as ordinary decimal strings. Numeric IPv4 tie order compares the four integer octets left to right, not the textual address strings.

Example

files = [[
 'time="t" msg="GET https://api.example/a HTTP/2.0 from 10.0.0.2:12 - 200 4B"',
 'time="t" msg="redirecting" Client IP="10.0.0.9:15"',
 'time="t" msg="POST https://api.example/b HTTP/1.1 from 10.0.0.2:13 - 500 0B"'
], [
 'time="t" msg="GET https://api.example/c HTTP/1.1 from 10.0.0.10:14 - 200 4B"',
 'time="t" msg="no pending executions"'
]]
result = [["10.0.0.2","2"],["10.0.0.10","1"]]

Explain how you would read an actual archive incrementally without loading all files into memory. Distinguish a high request count from proof that an address is malicious.