This document introduces the design and analysis of algorithms, emphasizing the importance of studying algorithms for achieving efficient computation. An algorithm is defined as a sequence of steps to transform input into output, and the analysis involves comparing algorithms based on time and space. The document also outlines fundamental characteristics of algorithms and distinguishes between algorithms, pseudo code, and programs.

1. Design and analysis of
algorithms
Introduction to DAA Lec 1

2. Why we need to study this subject?
 This course introduces the design and analysis of algorithms.
 Perhaps it is meaningful to discuss a very important question first: Why should we
study algorithms?
 It is commonly believed that in order to obtain high speed computation, it suffices
to have a very high speed computer.
 This, however, is not entirely true. We illustrate this with an experiment whose
results make it clear that a good algorithm implemented on a slow computer may
perform much better than a bad algorithm implemented on a fast computer.

3. Design and analysis of algorithm
Problem
Data structure
Algorithm
Program
Computer
+
Input Output

4. What is algorithm
 The word algorithm comes from name of Persian author “Abu Jaffar Mohammad” in
825AD.
 Def
An algorithm is a sequence of computational steps that transform the input into
the output.
 Another def.
Finite set of steps to solve a problem.

5. What is analysis
 Analysis is process of comparing two algorithms w.r.t time and space.
 Analysis can be of two types
1:Prior
Analysis before execution
Independent of hardware just focus on iterations
Give approx. value
2:Posterior
Analysis after execution
Always depend on hardware
Give exact value

6. Fundamentals for algorithm
 Input (zero input or more input)
 Output (at least one)
 Definiteness ( no confusion for computer, unambigious)
 Finiteness (always terminate)
 Effectiveness

7. Design of algorithms
Different ways of representing an algorithm is
 Natural language
 Pseudo code
 Flow chart

8. Fields in this course
 How to device algorithm?
 How to validate?
 How to analyse ?
 How to test?

9. Difference between algorithm, pseudo
code and program
 Algorithm
 A step by step method to
solve a problem .
 Its written in natural
language.
 For example a recipe for
preparing a dish.
 Program
 It is exact code in
any particular
programming
language.
 Pseudo code
 It is simple version of
programing code that does
not require any strict
programming language
syntax.