Time - Alex #15

codesrobertson · 2020-09-14T05:08:25Z

Hash Table Practice

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Question	Answer
Why is a good Hash Function Important?	Hash tables make lookups faster--average case scenario is constant time, I believe.
How can you judge if a hash function is good or not?	If it's fast at looking up keys, and if it allows for uniform distribution.
Is there a perfect hash function? If so what is it?	I don't think there is one; collisions are rare, but unavoidable.
Describe a strategy to handle collisions in a hash table	Double hashing, linear and quadratic probing, and separate chaining are some strategies for handling collisions.
Describe a situation where a hash table wouldn't be as useful as a binary search tree	If the max or min of a collection is sought, a BST has better time complexity.
What is one thing that is more clear to you on hash tables now	That there are several ways of handling collisions.

CheezItMan

Alex, nicely done. You hit all the learning goals here. Well done

CheezItMan · 2020-09-14T19:21:28Z

lib/exercises.rb

+# Time Complexity: O(n) (n being size of array)
+# Space Complexity: O(n)

 def grouped_anagrams(strings)


CheezItMan · 2020-09-14T19:21:51Z

lib/exercises.rb

+# Time Complexity: O(n log n)
+# Space Complexity: O(n)
 def top_k_frequent_elements(list, k)


👍 , Correct where n is the number of distinct elements.

Adds hash problems.

1e04452

CheezItMan reviewed Sep 14, 2020

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