ChallengeGenerate matching shard id
Here is something that came up that I liked as task to handle in a job interview. We have the following function, generating a shard id from a document key:
There is a need to create a new document that must reside on the same shard as another document. The task is to write a function that would generate that id.
- Key to match: users/71
- Document id to modify: orders/654
The result can be: orders/654-22261 or orders/654-vaueaa
In other words, both orders/654-vaueaa and users/71 will have the same shard.
I like this because it is very easy to explain and has simple coding requirements. But it allows to go deep into several different fields of knowledge to understand the candidate’s solution.
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Brute forcing it? Seems pretty fast ...
orders/654-usw gives a collision too
What code did you use for this?
There is probably a clever way to do this, but not knowing the intricacies of MD5, I just brute forced it :)
Ryan, You don't need to understand MD5. It is a cryptographic hash function, you can assume that you can control it.Your method would work just fine.