Day 23: Hash Tables
Hash Tables #
Welcome to Day 23 of our 60 Days of Coding Algorithm Challenge! Today, we’ll dive into Hash Tables, a fundamental data structure that provides efficient insertion, deletion, and lookup operations. Hash tables are widely used in various applications due to their average-case constant time complexity for these operations.
What is a Hash Table? #
A hash table is a data structure that implements an associative array abstract data type, a structure that can map keys to values. It uses a hash function to compute an index into an array of buckets or slots, from which the desired value can be found.
How Hash Tables Work #
- Hash Function: Converts keys into array indices.
- Collision Resolution: Handles cases where two keys hash to the same index.
Hash Functions #
A good hash function should:
- Be deterministic: same input always produces the same output.
- Distribute keys uniformly across the array.
- Be efficient to compute.
Example of a simple hash function:
1def simple_hash(key, table_size):
2 return sum(ord(char) for char in str(key)) % table_size
Collision Resolution Techniques #
1. Chaining #
In chaining, each bucket is …
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