~The most beautiful data structure ;)

1. Introduction to Hash Tables

A hash table is a data structure that maps keys to values using a hash function to compute an index into an array of buckets or slots. The goal is to store and retrieve data efficiently, often with constant time complexity, O(1), in the average case.

How It Works:

• A hash function converts the key into a fixed-size integer (hash value), which corresponds to an index in an internal array.
• The key-value pair is stored in the position indicated by this index.

Example:

If the key is "apple" and the hash function computes an index of 3, the value associated with "apple" will be stored in slot 3 of the array.

Advantages:

• Efficient lookup, insertion, and deletion operations.
• On average, these operations take constant time, O(1), making hash tables extremely efficient for large datasets.

2. Collisions in Hash Tables

A collision occurs when the hash function generates the same index for two different keys. For example, if both "apple" and "banana" hash to index 3, a collision happens. Since two values can’t occupy the same slot, we need strategies to resolve collisions.

3. Collision Avoidance Strategies

To deal with collisions, we use techniques like open addressing (linear probing, quadratic probing) or separate chaining. These strategies help maintain efficiency by ensuring all keys can still be stored and accessed.