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In this lesson, learn how computer science skills are applicable across a large range of topics and fields, through the lens of a young go-getter named Kenny.

Survey of Computer Science - The Tale of Kenny

Kenny's first job out of college is teaching high-school algebra. It's a normal day in school and Kenny needs to break the class up into pairs for a project. Sounds easy enough, but Kenny wants to match the students who are struggling with those who understand the material. 

Kenny looks at the problem and thinks to himself, "You know what? I'll use an algorithm to pair up these students!"

Kenny quickly writes up his class roster using the Python programming language and writes a program that pairs the highest scoring student with the lowest scoring student, the second highest scoring student with the second lowest scoring student, and so on.

What does that mean?

An algorithm is a step-by-step solution to a general type of problem. To solve this student-pairing problem, Kenny needs to write a sorting algorithm. 


Kenny the Teacher

Meet Kenny. Kenny is a bright young man who recently graduated from a prestigious university with a degree in Computer Science. But Kenny is a little disillusioned. He isn't sure that he wants to go into software engineering or even be a part of the technology industry at all.

Kenny thinks to himself, "how will I ever use any of these computer science skills out in the real world?"

Kenny is not unique. Often the realm of computer science can feel indescribably abstract and arcane, even to those who study it. But in fact, the same abstractness that makes computer science feel inaccessible also makes it incredibly useful and applicable to a wide range of fields, disciplines, and industries. Computer Science isn't just about learning how to code and program, it's about learning how to view the world in a different way, to see patterns that emerge from the mundane, and to reveal opportunities for optimization and improvement around every corner.

Over the course of this lesson, we will follow Kenny as he pursues a variety of different careers and hobbies and discovers that his computer science background is more relevant to his everyday life than he could have ever imagined.

What is Computer Science?

Although it was interesting and fun, Kenny didn't feel that the farm life was quite right for him. But his time on the farm made him interested in food and food safety, so Kenny became a health inspector.

In his job as a health inspector, he had to give the restaurants he inspected a grade. In order to grade them fairly, Kenny knew he had to develop a system to decide their score based on a set of conditions of the restaurant.

 Kenny would check each area in the restaurant in sequence: first the dining room, then the bar, then the servers station, and finally the kitchen.

If he found any pests, dirt, or something unsanitary at any of those locations he would subtract a letter from the overall grade of the restaurant. The restaurants always started with an *A*, but by the end of the inspection sometimes they ended up having an *F*, and no one wants to eat at a restaurant with an *F* health grade.

Kenny knew that what he had developed was a control flow. He had a set sequence he followed, and throughout that sequence, based on some conditionals he would lower the health grade of the establishment. This is a way of thinking that he learned when developing software. Kenny had turned his job as a health inspector into a sequence of if/then statements within a control flow. This allowed him to grade each restaurant fairly and consistently.

Control Flow and Logic

Algorithms have three main characteristics:

- They are **sequential**.
 - Algorithms are performed step by step from start to finish. Kenny's algorithm had to first build one pair of students, then another pair, then another pair, until all the students were paired up.
- They are **conditional**.
 - Algorithms perform certain steps based on conditions of the system. Kenny's algorithm needs to check the grade of each student as it builds the pairs to make sure that the highest scoring student is paired with the lowest scoring student and so forth.
- They are **generalizable**.
 - Algorithms are applicable to many different problems that are of a similar type. For example, Kenny used his sorting algorithm to pair students in each of his different classes and then, later in the day, he also used it to build a tournament bracket for the school's chess club. These are two different applications, but the generalizable nature of the sorting algorithm allowed it to be used in both situations.

What would have been a pretty annoying task to do by hand became an easy job for the computer. This is the power of algorithms! Nearly every piece of technology in the world today uses some form of algorithms to sort, store, and access data efficiently and accurately. 

Studying computer science gives you the tools you need to apply algorithmic thinking to real-world problems and quickly complete tasks and optimize processes that would have otherwise been a burden to tackle. Kenny doesn't know it yet, but algorithms are going to help him a lot in all sorts of situations!

What are Algorithms?

Kenny is exhausted and frustrated. After all of these different jobs and roles he still feels no closer to discovering what he really wants to do with his life. He turns to his friend Mimiko for advice. "What should I do Mimiko? I feel as lost as ever!" 

"Well," she says "you seemed to enjoy all of these jobs to a certain extent. What did they all have in common?"

Kenny thinks, hmm, what DID they all have in common? "Well, I used my understanding of computer science topics to help make my work more efficient, reliable, and repeatable!" That's it! Computer science! Huzzah!

He realizes that all this time in all of these roles he had been practicing the fundamentals of computer science, but without a computer! Clearly that is where his passion must lie.

This is the power of studying computer science. Learning the fundamental building blocks of how to optimize, how to build a process and control flow, and how to make sure your work is scalable will allow you to abstract these concepts into literally any field you might find yourself in.

In our modern world, nearly every industry employs software engineers in some capacity. Having a strong understanding of computer science principles will give you the skills you need to excel in any discipline, even the ones where you least expect it. Although Kenny took the long way around, he now finds himself back in the fold, developing software to make people's lives better, easier, and fuller.


Abstraction

Kenny saw the horrors of the food safety world but rather than those horrors driving him away, he thinks "I can do better!" and decides to take a job as a line cook at a local breakfast spot.

The place is popular and on weekend mornings there is quite a brunch rush. Sometimes Kenny has to make five or more bacon egg and cheese sandwiches at once! 

He turns to his knowledge of computer science again. "Well, if I think of the rush as a list of orders, I can iterate through the list and do a step at a time for each sandwich, completing all of the bacon, egg, and cheeses at once!"

So first Kenny puts the eggs for all five sandwiches on the grill, then he iterates through the orders and adds cheese to each one. Next, comes the bacon, he iterates through the list of orders and adds the bacon. Finally, the sandwiches are ready and he plates up each sandwich on a bagel. By iterating through his orders and performing the same operation on each of them, Kenny simplified his cooking process and delivered all five sandwiches on time!

This idea of iteration is essential to computer science and is used in practically every type of application. When you need to perform the same operation on every item in a list, you iterate through the list to complete that task. Almost all algorithms depend on some sort of iteration to produce their results, and by studying computer science you will see not only how to iterate through lists and data structures, but how to iterate _efficiently_ to complete a task in the optimum amount of time.

Iteration

Being a line cook was a lot harder than Kenny thought! He wanted to find some more relaxing work so Kenny went and got a job at the small rare bookstore in town. Kenny finds that most of his time working at the bookstore is spent searching for rare books that customers request.

Sadly, the store isn't separated into sections or labeled well, so Kenny finds himself going through row after row of books without any real direction. After a couple times of trying to look through every book from start to finish to find the one he needs, Kenny knows he needs to think of a better method, to optimize his search.

The good news is that the books are in alphabetical order, so Kenny thinks back to when he had to optimize searches when he was studying computer science and comes up with an idea. First, he'll start on a middle shelf and check the name of the author there. If that author comes later in the alphabet than the one he's looking for, he knows he only has to check the shelves on the left. If it comes before the author he's looking for he only has to check the shelves on the right.

He can then repeat this method on whichever side of the store the book must be on and slowly narrow down the area where the book must be. After repeating this process a couple times he is able to pinpoint the book and find it for the customer. Kenny knows that what he ended up implementing was a _binary search_, in computer science terms, and it ended up being able to effectively optimize his search time and reduce the amount of shelf scanning he had to do by several fold.

Once again, his background in computer science is paying off! 

Optimization

Kenny got tired of the classroom and wanted to see more of the outdoors, so he took a job as a farmhand. Kenny, being the capable young man he is, quickly moved up the ranks of the farmhand hierarchy and was tasked with managing a team of new farmhands to harvest the strawberry fields.

"How do I impart my knowledge of harvesting strawberries to these apprentice pickers?" thinks Kenny to himself. Well, whenever Kenny has a task that needs to be done many times over, like harvesting a strawberry, he thinks back to his computer science days and realizes he needs to write a _function_.

A **function** is a specific set of repeatable instructions that takes an input, like a strawberry plant, and produces an output, like freshly picked strawberries. If this sounds like the definition of an algorithm, you're right! An algorithm is conceptual, and a function can put an algorithm into practice.

Kenny finds it helpful to consider functions as he writes instructions on how to harvest strawberries for all of the new pickers. "I need to have explicit, step by step instructions or my pickers will not consistently produce the correct output," thinks Kenny. By thinking of these instructions as a function he is giving to the harvesters, Kenny ensures that harvesting strawberries is a repeatable, dependable task.