Design and analysis of algorithm lec 1.pptx
- 1. Design and analysis of algorithms Introduction to DAA Lec 1
- 2. Why we need to study this subject? ïŽ This course introduces the design and analysis of algorithms. ïŽ Perhaps it is meaningful to discuss a very important question first: Why should we study algorithms? ïŽ It is commonly believed that in order to obtain high speed computation, it suffices to have a very high speed computer. ïŽ 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 ïŽ The word algorithm comes from name of Persian author âAbu Jaffar Mohammadâ in 825AD. ïŽ Def An algorithm is a sequence of computational steps that transform the input into the output. ïŽ Another def. Finite set of steps to solve a problem.
- 5. What is analysis ïŽ Analysis is process of comparing two algorithms w.r.t time and space. ïŽ 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 ïŽ Input (zero input or more input) ïŽ Output (at least one) ïŽ Definiteness ( no confusion for computer, unambigious) ïŽ Finiteness (always terminate) ïŽ Effectiveness
- 7. Design of algorithms Different ways of representing an algorithm is ïŽ Natural language ïŽ Pseudo code ïŽ Flow chart
- 8. Fields in this course ïŽ How to device algorithm? ïŽ How to validate? ïŽ How to analyse ? ïŽ How to test?
- 9. Difference between algorithm, pseudo code and program ïŽ Algorithm ïŽ A step by step method to solve a problem . ïŽ Its written in natural language. ïŽ For example a recipe for preparing a dish. ïŽ Program ïŽ It is exact code in any particular programming language. ïŽ Pseudo code ïŽ It is simple version of programing code that does not require any strict programming language syntax.