Program: BE (Computer Engineering & Information Technology)
Class: SE
Course: Data Structure & Algorithm
Unit 01: Introduction to DSA & Hashing
Introduction to Data Structure & Algorithms

Data a collection of discrete or continuous values that convey
information, describing the quantity, quality, fact, statistics,
other basic units of meaning, or simply sequences of symbols
that may be further interpreted formally.
 Data : Information in a form a computer can use.
 Information : Any knowledge that can be communicated.
 A data structure is a specialized format for organizing,
processing, retrieving and storing data. There are several basic
and advanced types of data structures, all designed to arrange
data to suit a specific purpose. Data structures make it easy for
users to access and work with the data they need in appropriate
ways.
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Introduction to Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Why Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Why Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Why Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Why Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Why Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Why Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Why Data Structure & Algorithms
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hashing
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hashing
 Components of Hashing
 There are majorly three components of hashing:
 Key: A Key can be anything string or integer which is fed as input
in the hash function the technique that determines an index or
location for storage of an item in a data structure.
 Hash Function: The hash function receives the input key and
returns the index of an element in an array called a hash table. The
index is known as the hash index.
 Hash Table: Hash table is a data structure that maps keys to values
using a special function called a hash function. Hash stores the data
in an associative manner in an array where each data value has its
own unique index.
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hash Function
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Modular Hash Function
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Modular Hash Function
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Modular Hash Function
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hash Table
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hash Table
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hash Table
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hash Table
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
04
Collision
 Collision
 The hashing process generates a
small number for a big key, so there
is a possibility that two keys could
produce the same value. The
situation where the newly inserted
key maps to an already occupied,
and it must be handled using some
collision handling technology.
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
Collision
How to handle Collisions?
 There are mainly two methods to
handle collision:

Separate Chaining:

Open Addressing:
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Separate Chaining
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Separate Chaining
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Separate Chaining
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Separate Chaining
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04
Hashing
Applications of Hash Data structure
 Hash is used in databases for indexing.
 Hash is used in disk-based data structures.
 In some programming languages like Python, JavaScript hash is
used to implement objects.
Real-Time Applications of Hash Data structure
 Hash is used for cache mapping for fast access to the data.
 Hash can be used for password verification.
 Hash is used in cryptography as a message digest.
 Rabin-Karp algorithm for pattern matching in a string.
 Calculating the number of different substrings of a string.
www.sandipuniversity.edu.in
Department of Computer Engineering,
PVGCOE&SSDIM, Nashik
04