Hi, I'm Eli đź‘‹
@elibelly
UI Developer
Get your Computer Science degree
in 10 minutes*
@elibelly
*Here are some CS concepts that you might want to know exist or maybe clarifyÂ
@elibelly
What is computer science?
@elibelly
The study of problem solving
Looking at a problem and working out a way a computer might be able to help you solve it.
@elibelly
 The scientific and practical approach to computation and its applications.
 The systematic study of the feasibility, structure, expression, and mechanization of the methodical procedures (or algorithms) that underlie the acquisition, representation, processing, storage, communication of, and access to information.
More formally...
@elibelly
we want to, like, get information or do stuff to it soo how do we science that and then make computers do all the work real fast
Which basically means...
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Algorithms
@elibelly
What is an algorithm ?Â
An unambiguous set of steps to complete a task or computation
Â
It is very much like a recipe for a computer
@elibelly
Algorithm: Find the maxÂ
Problem: Given a list of positive numbers, we need to return the largest number on the list.
Input: A list, "L", of positive numbers. This list must contain at least one number.Â
Output: A number, "n", which will be the largest number of the list.
 Set "max" to 0.
 For each number x in the list L, compare it to max. If x is larger, set max to x.
 "max" is now set to the largest number in the list.
@elibelly
Algorithms & Computer ScienceÂ
 Does an algorithm actually exist to do a thing?
 Are we totally sure that the algorithm works for all possible inputs?
 How long does the algorithm take to run?
 How much memory space does it require?
 Once we know itâ€™s possible to solve a problem with an algorithm, is the algorithm the best possible one. Can the problem be solved more quickly?
Answering some Qs
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Time Complexity
The amount of time an algorithm takes to run in relation to the number of inputs
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Big O Notation
A mathematical notation that describes aÂ measure of the execution of a function as the inputs approach infinityÂ
O( ? )
Example: O( 1 ) , O( n ), O( log n ) where n represents the number of inputsÂ
@elibelly
Let's say you want to watch a box set....
Download  Order Online  

@elibelly
Let's say you want to watch a box set....
Download  Order Online  

10 episodes  10 hours  16 hours 
@elibelly
Let's say you want to watch a box set....
Download  Order Online  

10 episodes  10 hours  16 hours 
50 episodes  50 hours  16 hoursÂ 
@elibelly
Let's say you want to watch a box set....
Download  Order Online  

10 episodes  10 hours  16 hours 
50 episodes  50 hours  16 hoursÂ 
n episodes  n hours  16 hours 
Time complexity  O( n )  O( 1 ) 
Conclusion: Ordering Online is a more scalable algorithm!
@elibelly
What is the time complexity of searching for a maximum number in an array?Â
[ 34, 7, 0, 4, 12, 11, 104, 3, 19 ]
O(n)
@elibelly
Data Structures
A data structure is a particular way of organizing data in a computer so that it can be used efficiently
 Array*
 Linked List
 Stack*
 Queue*
 Tree*
 Heap
 Graph*
 Hash Map
@elibelly
Stack
Queue
pop()
push(book)
enqueue(person) //add
dequeue()
//remove
đź‘€peek()
đź¤”isEmpty()
đź‘€peek()
đź¤”isEmpty()
LIFO
Last In, First Out ordering
FIFO
First In, First Out ordering
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Trees
Graphs
Nodebased data structures. A tree is a type of graph.
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Analyzing Time Complexity of Algorithmic Operations on Data Structures
(adding it all together)
@elibelly
Doing things to information
 Search
 Sort
 Insert
 Find
 Delete
@elibelly
Algorithm: Find the maxÂ
Problem: Given a list of positive numbers, we need to return the largest number on the list.
Input: A list, "L", of positive numbers. This list must contain at least one number.Â
Output: A number, "n", which will be the largest number of the list.
 Set "max" to 0.
 For each number x in the list L, compare it to max. If x is larger, set max to x.
 "max" is now set to the largest number in the list.
@elibelly
Unsorted Array
Binary Search Tree
[ 3, 5, 20, 11, 8 ]
[ 8, 3, 11, 5, 20 ]
3
20
11
8
5
Time Complexity O(n)
Time Complexity O(log n)
Sorted Array
Unbalanced Tree
[ 20, 11, 8, 5, 3 ]
Time Complexity O(1)
20
11
8
5
Time Complexity O(n)
@elibelly
Other Topics in Computer Science

Programming Language TheoryÂ

Artificial Intelligence

Databases

Networking

Graphics

Cybersecurity

HumanComputer Interaction

Operating Systems

Compiler TheoryÂ

Distributed Systems

Boolean Logic

Number Theory

Game Theory

Bioinformatics

Big Data
@elibelly
đź‘‹
THANKS!
@elibelly
Get your CS degree in 10 minutes*
By Eli SchĂĽtze RamĂrez
Get your CS degree in 10 minutes*
Brief introduction to some Computer Science concepts for codebar monthlies.
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