Hashing in Data Structure - GeeksforGeeks (2024)

Introduction to Universal Hashing in Data Structure

Universal hashing is a technique used in computer science and information theory for designing hash functions. It is a family of hash functions that can be efficiently computed by using a randomly selected hash function from a set of hash functions. The goal of universal hashing is to minimize the chance of collisions between distinct keys, which c

Static Data Structure vs Dynamic Data Structure

Data structure is a way of storing and organizing data efficiently such that the required operations on them can be performed be efficient with respect to time as well as memory. Simply, Data Structure are used to reduce complexity (mostly the time complexity) of the code. Data structures can be two types : 1. Static Data Structure 2. Dynamic Data

Encryption vs Encoding vs Hashing

Pre-Requisite: Encryption, Encoding, Hashing. Encryption, Encoding, and Hahsing are similar kinds of things and have little difference between them. They all are used to change the format of the data or data transformation for different purposes. We will discuss them separately. Let us first discuss the definition of all these three processes and t

Practice Problems on Hashing

In this article, we will discuss the types of questions based on hashing. Before understanding this, you should have idea about hashing, hash function, open addressing and chaining techniques (see: Introduction, Separate chaining, Open addressing). These are some key points in hashing: The purpose of hashing is to achieve search, insert and delete

Coalesced hashing

Coalesced hashing is a collision avoidance technique when there is a fixed sized data. It is a combination of both Separate chaining and Open addressing. It uses the concept of Open Addressing(linear probing) to find first empty place for colliding element from the bottom of the hash table and the concept of Separate Chaining to link the colliding

Find the smallest positive number missing from an unsorted array : Hashing Implementation

Given an unsorted array with both positive and negative elements including 0. The task is to find the smallest positive number missing from the array in O(N) time. Examples: Input: arr[] = {-5, 2, 0, -1, -10, 15} Output: 1 Input: arr[] = {0, 1, 2, 3, 4, 5} Output: 6 Input: arr[] = {1, 1, 1, 0, -1, -2} Output: 2 We can use hashing to solve this prob

Rearrange characters in a string such that no two adjacent are same using hashing

Given a string str with repeated characters, the task is to rearrange the characters in a string such that no two adjacent characters are the same. If it is possible then print Yes else print No. Examples: Input: str = "geeksforgeeks" Output: Yes "egeksforegeks" is one such arrangement. Input: str = "bbbbb" Output: No Approach: The idea is to store

Area of the largest square that can be formed from the given length sticks using Hashing

Given an array arr[] of N integers representing the heights of the sticks. The task is to find the area of the largest square that can be formed using these sticks and the count of such squares. Note that a single side of the square can only use a single stick.Examples: Input: arr[] = {5, 3, 2, 3, 6, 3, 3} Output: Area = 9 Count = 1 Side of the squ

Full domain Hashing with variable Hash size in Python

A cryptographic hash function is a special class of hash function that has certain properties which make it suitable for use in cryptography. It is a mathematical algorithm that maps data of arbitrary size to a bit string of a fixed size (a hash function) which is designed to also be a one-way function, that is, a function which is infeasible to in

Folding Method in Hashing

Folding Method in Hashing: It breaks up a key value into precise segments that are added to form a hash value, and look at another technique is to apply a multiplicative hash function to each segment individually before adding. Some folding methods go one step further and reverse every other piece before the addition. This folding method is indepen

What is the difference between Hashing and Hash Tables?

What is Hashing? Hashing refers to the process of generating a fixed-size output from an input of variable size using the mathematical formulas known as hash functions. This technique determines an index or location for the storage of an item in a data structure. It might not be strictly related to key-value pairs only if you are manipulating the d

Hashing meaning in DSA

Hashing is defined as a data distribution technique that transforms given key into a different value using hash function for faster access to data. Characteristics of Hashing:Hashing maps the data object to exactly one memory bucket.It allows uniform distribution of keys across the memory.Uses different functions to perform hashing such as mid squa

Address Calculation Sort using Hashing

In this sorting algorithm, Hash Function f is used with the property of Order Preserving Function which states that if [Tex]x <= y, f(x) <= f(y) [/Tex]. Hash Function: f(x) = floor( (x/maximum) * SIZE )where maximum => maximum value in the array, SIZE => size of the address table (10 in our case), floor => floor functionThis algorith

Longest Palindromic Substring using hashing in O(nlogn)

Given a string S, The task is to find the longest substring which is a palindrome using hashing in O(N log N) time. Input: S: ”forgeeksskeegfor”, Output: “geeksskeeg” Input: S: ”Geeks”, Output: “ee” Hashing to Solve the Problem:The hashing approach to solving the longest palindromic substring problem uses a hash table to store the characters of the

Convert an Array to reduced form using Hashing

Given an array with N distinct elements, convert the given array to a form where all elements are in the range from 0 to N-1. The order of elements is the same, i.e., 0 is placed in the place of the smallest element, 1 is placed for the second smallest element, ... N-1 is placed for the largest element. Examples: Input: arr[] = {10, 40, 20}Output:

Minimax Algorithm in Game Theory | Set 5 (Zobrist Hashing)

Previous posts on this topic : Minimax Algorithm in Game Theory, Evaluation Function in Game Theory, Tic-Tac-Toe AI – Finding optimal move, Alpha-Beta Pruning.Zobrist Hashing is a hashing function that is widely used in 2 player board games. It is the most common hashing function used in transposition table. Transposition tables basically store the

Index Mapping (or Trivial Hashing) with negatives allowed

Index Mapping (also known as Trivial Hashing) is a simple form of hashing where the data is directly mapped to an index in a hash table. The hash function used in this method is typically the identity function, which maps the input data to itself. In this case, the key of the data is used as the index in the hash table, and the value is stored at t

Implement Phone Directory using Hashing

Hashing is a technique that uses fewer key comparisons and searches the element in O(n) time in the worst case and in O(1) time in the average case. The task is to implement all functions of phone directory: create_record display_record delete_record search_record update_record Following data will be taken from the client: ID, Name, Telephone numbe

What is Hashing?

Hashing refers to the process of generating a fixed-size output from an input of variable size using the mathematical formulas known as hash functions. This technique determines an index or location for the storage of an item in a data structure. Need for Hash data structureThe amount of data on the internet is growing exponentially every day, maki

Mid-Square hashing

Mid-Square hashing is a hashing technique in which unique keys are generated. In this technique, a seed value is taken and it is squared. Then, some digits from the middle are extracted. These extracted digits form a number which is taken as the new seed. This technique can generate keys with high randomness if a big enough seed value is taken. How

Double Hashing

Double hashing is a collision resolution technique used in hash tables. It works by using two hash functions to compute two different hash values for a given key. The first hash function is used to compute the initial hash value, and the second hash function is used to compute the step size for the probing sequence. Double hashing has the ability t

Implement Secure Hashing Algorithm - 512 ( SHA-512 ) as Functional Programming Paradigm

Given a string S of length N, the task is to find the SHA-512 Hash Value of the given string S. Examples: Input: S = "GeeksforGeeks"Output: acc10c4e0b38617f59e88e49215e2e894afaee5ec948c2af6f44039f03c9fe47a9210e01d5cd926c142bdc9179c2ad30f927a8faf69421ff60a5eaddcf8cb9c Input: S = "hello world"Output:309ecc489c12d6eb4cc40f50c902f2b4d0ed77ee511a7c7a9bc

Crossword Puzzle Of The Week #35 (For Hashing)

In this issue of Crossword Puzzle of the Week, we will dive into the topic of Hashing data structure. The solution to the crossword puzzle is provided at the end. HINTS: Down: 1. The idea behind separate _______ is to implement the array as a linked list called a chain.3. The situation where the newly inserted key maps to an already occupied, and i

Cuckoo Hashing in Python

Cuckoo Hashing derived its name from the cuckoo bird, which lays its eggs in the nests of other birds, replacing their eggs with its own. Cuckoo Hashing works in a similar manner which involves moving the values to different location whenever there is a collision in the hash table. In this article, we will learn how to implement Cuckoo Hashing in P

Double Hashing in Python

Double hashing is a collision resolution technique used in hash tables. It works by using two hash functions to compute two different hash values for a given key. The first hash function is used to compute the initial hash value, and the second hash function is used to compute the step size for the probing sequence. In this article, we'll explore w

Top 20 Hashing Technique based Interview Questions

Find whether an array is subset of another arrayUnion and Intersection of two Linked ListsFind a pair with given sumFind Itinerary from a given list of ticketsFind four elements a, b, c and d in an array such that a+b = c+dFind the largest subarray with 0 sumCount distinct elements in every window of size kFind smallest range containing elements fr

Hashing in Competitive Programming

Hashing is a fundamental technique in competitive programming that is used to efficiently manipulate and process large amounts of data. Data Structures like Hash Maps and Hash Sets use hashing techniques to provide faster insertion, deletion and retrieval of values. Table of Content What is Hashing?Why use Hashing in Competitive Programming?Advanta

Quadratic Probing in Hashing

Hashing is an improvement technique over the Direct Access Table. The idea is to use a hash function that converts a given phone number or any other key to a smaller number and uses the small number as the index in a table called a hash table. Hash Function: A function that converts a given big number to a small practical integer value. The mapped

Separate Chaining Collision Handling Technique in Hashing

Separate Chaining is a collision handling technique. Separate chaining is one of the most popular and commonly used techniques in order to handle collisions. In this article, we will discuss about what is Separate Chain collision handling technique, its advantages, disadvantages, etc. What is Collision? Since a hash function gets us a small number