# What Is Hashing Algorithm in Data Structure?

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Scott Campbell

A hashing algorithm is an essential concept in the field of data structures. It plays a crucial role in various applications and is used to efficiently store and retrieve data. In this article, we will dive into the world of hashing algorithms, exploring what they are and how they work.

## What Is Hashing?

Hashing is a technique used to convert data of any size into a fixed-size value. The result of this conversion is called a hash value or simply a hash. The primary purpose of hashing is to provide faster access to data by mapping it to a unique index within a fixed-size array or table.

When we store data in a hash table, we use a hashing algorithm to compute the hash value for each item. This hash value acts as an index where the item will be stored.

## How Does Hashing Work?

The process of hashing involves several steps:

1. The hashing algorithm takes the input data and performs computations on it.
2. These computations generate a unique hash value for each input.
3. The hash value is then used as an index to store or search for the corresponding data in the hash table.

To understand this better, let’s consider an example:

We have a list of students’ names along with their corresponding roll numbers. We want to store this information in a hash table using their roll numbers as keys.

We can create our own simple hashing algorithm by taking the sum of ASCII values of each character in the roll number and dividing it by the size of our hash table. Let’s assume our hash table has 10 slots (0-9 indices).

For example, if we have a student with roll number “A12345”, we can calculate the hash value as follows:

Step 1: Convert each character to its ASCII value: ‘A’ = 65, ‘1’ = 49, ‘2’ = 50, ‘3’ = 51, ‘4’ = 52, ‘5’ = 53.

Step 2: Calculate the sum of ASCII values: 65 + 49 + 50 + 51 + 52 + 53 = 320.

Step 3: Divide the sum by the size of the hash table (10): 320 % 10 = 0.

Hence, our hash value for roll number “A12345” is 0. We can store this student’s information at index 0 in our hash table.

The use of hashing algorithms offers several advantages:

• Faster Data Retrieval: Hashing allows for constant-time retrieval of data. Once we know the hash value, we can directly access the corresponding data without iterating through a large collection.
• Data Integrity: Hashing ensures that data remains intact during storage and retrieval.

Even a small change in input data results in a significantly different hash value.

• Distributed Storage: Hashing enables efficient distribution and management of data across multiple servers or nodes. Each node can handle a specific range of hash values.

## Closing Thoughts

In conclusion, hashing algorithms are vital components in data structures. They provide efficient ways to store and retrieve data by mapping it to a unique index. Understanding how hashing works and the advantages it offers can greatly enhance your ability to design and implement high-performance applications.

So, the next time you encounter a large dataset or need to optimize data retrieval, consider employing a hashing algorithm to make your life easier!