**Hashing vs HashMap**
================================
hashing, hashmap, data structures, algorithms, programming, development

When it comes to storing and retrieving data efficiently, developers often rely on hash-based data structures like Hash Maps (HashMaps). But did you know that hashing is a fundamental concept that underlies many of these structures? In this 10-minute read, we'll dive into the world of hashing and explore its relationship with HashMaps. Let's get started!

**What is Hashing?**

Hashing is a process that takes an input (often a string or an object) and generates a fixed-size output, known as a hash code. This hash code represents the original data in a condensed form, making it easy to store, compare, and retrieve. Hash functions are designed to be fast, deterministic, and non-reversible, meaning you can't recover the original input from its hash code.

**What is a HashMap?**

A HashMap (or hash map) is a data structure that stores key-value pairs in an array-like format using hashing as its underlying mechanism. Each key is unique and maps to a specific value. When you insert a new pair, the HashMap uses a hash function to calculate the index where it should be stored. This allows for fast lookups, insertions, and deletions, making HashMaps ideal for applications that require efficient data retrieval.

**Hashing vs HashMap: The Connection**

Now that we've covered hashing and HashMaps individually, let's explore their connection. When you create a HashMap, the hash function is used to map keys to indices in the array. This process is known as key-to-index mapping. The resulting index serves as an array offset, allowing for fast access to the corresponding value.

Here's an ASCII diagram illustrating this concept:
```
+---------------+
|  Key         |
+---------------+
        |
        v
+---------------+
|  Hash Code    |
+---------------+
        |
        v
+---------------+
|  Index (array)|
+---------------+
```
The hash code is generated from the key, and the index is calculated based on that hash code. This efficient mapping enables fast lookups in HashMaps.

**Key Takeaways**

* Hashing is a fundamental concept used to generate fixed-size outputs from input data.
* A HashMap uses hashing as its underlying mechanism to store key-value pairs efficiently.
* The connection between hashing and HashMaps lies in the key-to-index mapping, where the hash code determines the index in the array.

**TL;DR**

In this brief overview, we explored the concepts of hashing and HashMaps. We saw how hashing generates fixed-size outputs from input data and how HashMaps use hashing to store key-value pairs efficiently. Understanding these fundamental concepts can help developers create more efficient and effective algorithms for their applications.

Time taken: 10 minutes