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请问你是用的coderpad还是自己的IDE？ 如果coderpad的话，test case是自己写还是里面已经带有基本的test了？

leros1 发表于 2021-2-28 07:55
请问你是用的coderpad还是自己的IDE？ 如果coderpad的话，test case是自己写还是里面已经带有基本的test了 ...

我用的是coderpad。test infrastructure就是手写的main()。最开始的test cases是题目里的，后来又自己加了些，最后的面试官也会加几个来验证。

请问一下是哪个题目呀？我积分不够看不到，谢谢

Part 1

In an HTTP request, the Accept-Language header describes the list of
languages that the requester would like content to be returned in. The header
takes the form of a comma-separated list of language tags. For example:

  Accept-Language: en-US, fr-CA, fr-FR

means that the reader would accept:

  1. English as spoken in the United States (most preferred)
  2. French as spoken in Canada
  3. French as spoken in France (least preferred)

We're writing a server that needs to return content in an acceptable language
for the requester, and we want to make use of this header. Our server doesn't
support every possible language that might be requested (yet!), but there is a
set of languages that we do support. Write a function that receives two arguments:
an Accept-Language header value as a string and a set of supported languages,
and returns the list of language tags that will work for the request. The
language tags should be returned in descending order of preference (the
same order as they appeared in the header).

In addition to writing this function, you should use tests to demonstrate that it's
correct, either via an existing testing system or one you create.

Examples:

parse_accept_language(
  "en-US, fr-CA, fr-FR",  # the client's Accept-Language header, a string
  ["fr-FR", "en-US"]      # the server's supported languages, a set of strings
)
returns: ["en-US", "fr-FR"]

parse_accept_language("fr-CA, fr-FR", ["en-US", "fr-FR"])
returns: ["fr-FR"]

parse_accept_language("en-US", ["en-US", "fr-CA"])
returns: ["en-US"]

Part 2

Accept-Language headers will often also include a language tag that is not
region-specific - for example, a tag of "en" means "any variant of English". Extend
your function to support these language tags by letting them match all specific
variants of the language.

Examples:

parse_accept_language("en", ["en-US", "fr-CA", "fr-FR"])
returns: ["en-US"]

parse_accept_language("fr", ["en-US", "fr-CA", "fr-FR"])
returns: ["fr-CA", "fr-FR"]

parse_accept_language("fr-FR, fr", ["en-US", "fr-CA", "fr-FR"])
returns: ["fr-FR", "fr-CA"]

Part 3

Accept-Language headers will sometimes include a "wildcard" entry, represented
by an asterisk, which means "all other languages". Extend your function to
support the wildcard entry.

Examples:

parse_accept_language("en-US, *", ["en-US", "fr-CA", "fr-FR"])
returns: ["en-US", "fr-CA", "fr-FR"]

parse_accept_language("fr-FR, fr, *", ["en-US", "fr-CA", "fr-FR"])
returns: ["fr-FR", "fr-CA", "en-US"]

Part 4

Accept-Language headers will sometimes include explicit numeric weights (known as
q-factors) for their entries, which are used to designate certain language tags
as specifically undesired. For example:

Accept-Language: fr-FR;q=1, fr;q=0.5, fr-CA;q=0

This means that the reader most prefers French as spoken in France, will take
any variant of French after that, but specifically wants French as spoken in
Canada only as a last resort. Extend your function to parse and respect q-factors.

Examples:

parse_accept_language("fr-FR;q=1, fr-CA;q=0, fr;q=0.5", ["fr-FR", "fr-CA", "fr-BG"])
returns: ["fr-FR", "fr-BG", "fr-CA"]

parse_accept_language("fr-FR;q=1, fr-CA;q=0, *;q=0.5", ["fr-FR", "fr-CA", "fr-BG", "en-US"])
returns: ["fr-FR", "fr-BG", "en-US", "fr-CA"]

parse_accept_language("fr-FR;q=1, fr-CA;q=0.8, *;q=0.5", ["fr-FR", "fr-CA", "fr-BG", "en-US"])

最后一小问我的想法是记录每个supported tag的q factor，比如一开始大家的q factor都是-1。然后根据用户输入，有*的话先处理*，接下来处理单独的language（比如fr, en）如果有的话，最后处理完整的tag（比如fr-FR, en-US），每次都更新对应的supported tag的q factor，最后选出所有q factor不是-1的supported tag然后根据q factor排序输出。这道题现场没写完，只说了个大概思路。

我没做到part 3 or 4.