FIRE - ALICE D

[codeandmorecode]

Hash Table Practice

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Comprehension Questions

Question	Answer
Why is a good Hash Function Important?	We can use them for encryption. It can be very time efficient also.
How can you judge if a hash function is good or not?	A hash function is a good one if we have fast computation of the hash value; hash values that are uniformly distributed; keys that are close have hash values that are far apart, and hashing appears to be random (hard to deduce the original object)
Is there a perfect hash function? If so what is it?	A hash function that has all the above features is close to being a perfect hash function.
Describe a strategy to handle collisions in a hash table	One strategy can be Separate Chaining which essentially just uses a linked list to store the collided keys
Describe a situation where a hash table wouldn't be as useful as a binary search tree	Hash tables are not good for finding ordered data. A binary search tree would be better in that case.
What is one thing that is more clear to you on hash tables now	It is more clear to me what makes up a good hash function.

[CheezItMan]

Nice work Alice. I did have a few comments on time complexity. Let me know if you have any questions regarding it. WEll done.

[CheezItMan]

👍 Nice work, just a note if the strings are limited in size, the time complexity is O(n), otherwise it is O(n * m log m) where n is the number of strings and m is the length of the strings.

[CheezItMan]

👍 Because you're sorting the (and not in a loop) your algorithm is O(n log n) because Ruby uses MergeSort internally.