JavaScript - Chapter 1 - Problem Solving

www.webstackacademy.com Problem Solving JavaScript

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www.webstackacademy.com Problem Solving – What? • An approach which could be taken to reach to a solution • The approach could be ad hoc or generic with a proper order • Sometimes it requires a creative and out of the box thinking to reach to perfect solution

www.webstackacademy.com BCD Problem Solving A  Introduction to SDLC  Polya’s Rules  Algorithm Design methods

www.webstackacademy.com BCD Problem Solving A  A Quick introduction to SDLC  Never jump into implementation – Why? o You might not have the clarity of the application o You might have some loose ends in the requirements o Complete picture of the application could be missing and many more...

www.webstackacademy.com Test Code Design Requirement • Understand requirements properly • Consider all possible I/P and O/P • Know boundary conditions • Get it verified • Implement code based on the design • Try to have maximum modularity • Coding practices like – Indentation, Commenting, Variable naming convention, Neat file and function headers • Have a proper design plan • Use some algorithm • Use pen and paper method • Use flow chart (if required) • Make sure all cases are covered • Test the implementation thoroughly • Capture all possible cases • Have neat output presentation • Requirements -> Output trace SDLC - Phases

www.webstackacademy.com BCD Problem Solving – How? A  Polya’s rule: o Understand the problem o Devise a plan o Carry out the plan o Look back

www.webstackacademy.com BCD Problem Solving – Algorithm – What? A  A procedure or formula for solving a problem  A sequence of unambiguous instructions for solving a problem. This means obtaining a required output for any legitimate input in a finite amount of time  Algorithms is needed to generate correct output in finite time in a given constrained environment: o Correctness of output o Finite time o Better Prediction  Steps to take: o Natural language (Step-by-step) o Pseudo codes o Flowcharts

www.webstackacademy.com BCD Problem Solving – Daily life example A  Let's consider a problem of reaching this room  The different possible approach could be thought of  Take a Walk  Take a Bus  Take a Car  Let's Pool  Lets discuss the above approaches in bit detail

www.webstackacademy.com BCD Algorithm – Reaching this room – Take a walk A  The steps could be like o Start a 8 AM o Walk through street X for 500 Mts o Take a left on main road and walk for 2 KM o Take a left again and walk 200 Mts to reach  Pros o You might say walking is a good exercise :) o Might have good time prediction o Save some penny  Cons o Depends on where you stay (you would choose if you stay closer) o Should start early o Would get tired o Freshness would have gone

www.webstackacademy.com BCD Algorithm – Reaching this room – Take a bus A  The steps could be like o Start a 8.30 AM o Walk through street X for 500 Mts o Take a left on main road and walk for 100 Mts to bus stop o Take Bus No 111 and get down at stop X and walk for 100 Mts o Take a left again and walk 200 Mts to reach  Pros o You might save some time o Less tiredness comparatively  Cons o Have to walk to the bus stop o Have to wait for the right bus (No prediction of time) o Might not be comfortable on rush hours

www.webstackacademy.com BCD Algorithm – Reaching the room – Take a car A  The steps could be like o Start a 9 AM o Drive through street X for 500 Mts o Take a left on main road and drive 2 KM o Take a left again and drive 200 Mts to reach+  Pros o Proper control of time and most comfortable o Less tiresome  Cons o Could have issues on traffic congestions o Will be costly

www.webstackacademy.com BCD Algorithm – Reaching the room – Let’s pool A  The steps could be like o Start a 8.45 AM o Walk through street X for 500 Mts o Reach the main road wait for you partner o Drive for 2 KM on the main road o Take a left again and drive 200 Mts to reach  Pros o You might save some time o Less costly comparatively  Cons o Have to wait for partner to reach o Could have issues on traffic congestions

www.webstackacademy.com BCD Algorithm – Reaching the room – Conclusion A  All the above solution eventually will lead you to this room  Every approach some pros and cons  It would be our duty as a designer to take the best approach for the given problem

www.webstackacademy.com BCD Algorithm – A computer example A  Let's consider a problem of adding two numbers  The steps involved : o Start o Read the value of A and B o Add A and B and store in SUM o Display SUM o Stop  The above 5 steps would eventually will give us the expected result

www.webstackacademy.com BCD Algorithm – Pseudo code A  Let's consider a problem of adding two numbers  The steps involved : BEGIN Read A, B SUM = A + B Print SUM END  The above 5 steps would eventually will give us the expected result

www.webstackacademy.com BCD Algorithm – Flowcharts A

www.webstackacademy.com BCD Algorithm – DIY - Pattern A  Write an algorithm to print the below pattern

www.webstackacademy.com BCD Algorithm – DIY - Pattern A  Write an algorithm to print the below number pyramid

www.webstackacademy.com BCD Algorithm – DIY – Try the following A  Finding largest of 2 numbers  Find the largest member of an array  Count the number of vowels  Count the number of occurrences of each vowel  To find the sum of n – natural numbers  Convert a number from base 10 to base N

www.webstackacademy.com BCD Algorithm – DIY – Try the following A Sand Timers: You have two sand timers, which can show 4 minutes and 7 minutes respectively. Use both the sand timers (at a time or one after other or any other combination) and measure a time of 9 minutes.

www.webstackacademy.com BCD Algorithm – DIY – Try the following A Mad men in a circle: N persons (given as the input by the user) are standing in a circle. They are labeled from 1 to N in clockwise order. The first person is holding a gun, will shoot a person on his right and pass the gun to the next person who is alive. • Assuming N = 100, what is the index of the last person who will be alive? • Can you write a generic algorithm which can handle N value up-to 1000? • Can you validate your output by writing a JavaScript program?

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JavaScript - Chapter 1 - Problem Solving

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JavaScript - Chapter 1 - Problem Solving