What Is An Algorithm? | What Exactly Is Algorithm? | Algorithm Basics Explained | Simplilearn

Summary

This video from Simply Learn's YouTube channel explores the concept of algorithms, their characteristics, and the process of writing them. It uses the analogy of making tea to illustrate an algorithm's step-by-step approach. The video covers algorithm analysis, complexities, and the differences between algorithms and programming, highlighting the advantages and disadvantages of using algorithms in problem-solving.

Takeaways

• 📘 An algorithm is a method or set of rules to be followed to perform calculations or solve problems, often represented as a step-by-step process.
• 🔍 The characteristics of an algorithm include clarity, well-defined inputs and outputs, feasibility, finiteness, and language independence.
• 📝 Writing an algorithm does not have strict rules and is not tied to a specific programming language; it should support conditional and iterative statements.
• 🔢 Algorithm analysis can be done priori (theoretical) and posterior (practical) to understand the time and space requirements of an algorithm.
• ⏱ Time complexity, expressed with Big O notation, measures the amount of time an algorithm takes to execute based on the number of steps.
• 📦 Space complexity, also expressed with Big O notation, calculates the amount of memory required by an algorithm to solve a problem.
• 🛠 Advantages of algorithms include their ease of understanding, step-by-step representation, and ability to break down problems into smaller parts.
• 🚫 Disadvantages include the time-consuming nature of writing algorithms and the difficulty in demonstrating branching and looping statements.
• 🌐 The main differences between algorithms and programming are that algorithms are problem-solving techniques, while programs are tasks performed by computers; algorithms can be executed by humans, whereas programs require compilers; and algorithms use natural language, while programs use programming languages.
• 📚 The tutorial provides a comprehensive overview of what algorithms are, how they are written, analyzed, and the complexities involved, as well as their advantages, disadvantages, and distinctions from programming.

Q & A

What is the main topic of the session presented in the video script?

The main topic of the session is to discuss what an algorithm is, its characteristics, how to write one, algorithm analysis and complexities, advantages and disadvantages, and the differences between algorithms and programming.

What is the real-life example given in the script to illustrate the concept of an algorithm?

The real-life example given is the process of making tea, where Shreya follows a series of steps to achieve the desired outcome of a cup of tea.

What are the six characteristics of an algorithm mentioned in the script?

The six characteristics are: clear and unambiguous, well-defined inputs, well-defined outputs, feasibility, finiteness, and language independence.

How is the process of making tea related to the concept of an algorithm in computer science?

The process of making tea is related to an algorithm in computer science as both involve a set of rules or steps that must be followed in a specific order to achieve a desired outcome.

What does the script suggest about the importance of clear and unambiguous steps in an algorithm?

The script suggests that clear and unambiguous steps are important because they make the algorithm straightforward, simple, easily readable, and lead to a single conclusion.

Why is it necessary for an algorithm to have well-defined inputs and outputs?

Well-defined inputs and outputs are necessary because they ensure that the algorithm can be expected to produce a specific outcome when given certain inputs, making it predictable and reliable.

What does the term 'finiteness' refer to in the context of algorithms?

Finiteness refers to the property that an algorithm must be finite, meaning it should not result in infinite loops or similar situations, and must terminate after a certain number of steps.

How does the script describe the process of writing an algorithm?

The script describes the process of writing an algorithm as not having hard and fast rules, being created to support conditional and iterative statements, and being developed in a step-by-step manner after the problem domain has been well-defined.

What are the two types of algorithm analysis mentioned in the script?

The two types of algorithm analysis mentioned are priori analysis, which is theoretical and performed before implementation, and post analysis, which is practical and performed after the algorithm is created to determine time and space requirements.

How is the time complexity of an algorithm expressed in the script?

The time complexity of an algorithm is expressed using the Big O notation, which is used to count the number of steps required to complete the task and is indicative of the algorithm's efficiency.

What are the advantages and disadvantages of algorithms as discussed in the script?

The advantages include ease of understanding, step-by-step representation, and breaking down problems into smaller steps. The disadvantages include the time-consuming nature of writing algorithms and the difficulty in demonstrating branching and looping statements.

What are the key differences between an algorithm and programming as outlined in the script?

The key differences are that an algorithm is a notation or technique for solving a problem, can be decoded by a human, is a design of the solution, and is written using natural language, whereas programming is directly associated with computers, run by compilers, involves implementation and testing, and is written in a programming language.

Outlines

00:00

📚 Introduction to Algorithms

This paragraph introduces the topic of algorithms, emphasizing the channel's commitment to daily updates on various technologies. It invites viewers to subscribe for the latest tech trends and highlights the session's agenda, which includes defining an algorithm, discussing its characteristics, how to write one, analyzing algorithms and their complexities, and the advantages and disadvantages of algorithms. The paragraph concludes with a real-life example of making tea to illustrate the concept of an algorithm in computer science, defined as a method or set of rules to perform calculations or solve problems through a sequence of steps.

05:00

🔍 Characteristics and Writing of Algorithms

This section delves into the characteristics of algorithms, outlining six key attributes: clarity, well-defined inputs and outputs, feasibility, finiteness, and language independence. It then explains the process of writing algorithms, which are not tied to any specific programming language and must support conditional and iterative statements. The paragraph provides an example of creating an algorithm to find the largest number among three, demonstrating different approaches to the same problem. It also introduces the concepts of priori and post analysis of algorithms, explaining the theoretical and practical aspects of algorithm evaluation.

10:02

🕒 Algorithm Analysis and Complexity

The focus of this paragraph is on algorithm analysis, discussing the theoretical (priori) and practical (post) analyses. It explains the purpose of these analyses, which is to determine the time and space requirements of an algorithm. The paragraph introduces the concepts of time complexity and space complexity, using big O notation to express these complexities. An example is given to illustrate time complexity, showing how the number of steps affects the efficiency of an algorithm. The explanation of space complexity includes the components considered when calculating it, such as program instructions, constant values, variable values, and auxiliary space.

🔄 Advantages, Disadvantages, and Differences Between Algorithms and Programming

The final paragraph discusses the pros and cons of algorithms. Advantages include their ease of understanding, step-by-step problem-solving approach, and the ability to break down complex problems. Disadvantages are noted, such as the time-consuming nature of writing algorithms and the difficulty in demonstrating branching and looping statements. The paragraph concludes by distinguishing between algorithms and programming, highlighting that algorithms are problem-solving techniques, whereas programs are tasks performed by computers. It also points out that algorithms can be understood by humans, while programs require compilers, and that algorithms are written in natural language, in contrast to programming languages used in coding.

Keywords

💡Algorithm

An algorithm is a set of rules or instructions that govern how a task should be performed step by step to achieve a desired outcome. It is central to the video's theme as it defines the concept being discussed. In the script, the tea-making process is used as a real-life example of an algorithm, illustrating the step-by-step nature of following a set of instructions.

💡Characteristics of Algorithm

These are the properties that define what an algorithm should be. The video outlines six key characteristics: clear and unambiguous, well-defined inputs and outputs, feasibility, finiteness, and language independence. These characteristics are essential for understanding how algorithms are structured and function, ensuring they can be implemented effectively.

💡Input

In the context of algorithms, input refers to the data provided to the algorithm that initiates the process. The script mentions that an algorithm should have well-defined inputs, which means the data required for the algorithm to start its operation must be clearly specified, as seen in the tea-making example where the ingredients are the inputs.

💡Output

Output in an algorithm is the result produced after processing the input data. The script emphasizes that algorithms should have well-defined outputs, indicating that the expected result of the algorithm must be clearly stated, like the ready-to-drink tea in the script's example.

💡Feasibility

Feasibility in the context of algorithms means that the steps outlined must be practical and executable with the available resources. The video explains that an algorithm must be simple, generic, and able to be executed, which is crucial for ensuring that the algorithm can be implemented in real-world scenarios.

💡Finiteness

Finiteness is a key characteristic of algorithms, which states that an algorithm must be finite and must not result in infinite loops. The script uses this term to explain that an algorithm should have a defined end, ensuring that it will not run indefinitely.

💡Language Independence

Language independence refers to the ability of an algorithm to be implemented in any programming language without being tied to a specific one. The video script explains this by stating that an algorithm should be defined in a way that it can be implemented using simple instructions, regardless of the programming language used.

💡Algorithm Analysis

Algorithm analysis involves evaluating the performance of an algorithm, both theoretically before implementation (priori analysis) and practically after implementation (post analysis). The script discusses this concept to highlight the importance of understanding the time and space requirements of an algorithm, which is crucial for assessing its efficiency.

💡Time Complexity

Time complexity is a measure of the amount of time an algorithm takes to complete as a function of the size of the input. The script introduces the Big O notation as a way to express time complexity, which is essential for comparing the efficiency of different algorithms, as demonstrated by the example of multiplying n numbers.

💡Space Complexity

Space complexity is the measure of the amount of memory space required by an algorithm to solve a problem. The script explains it with the Big O notation and discusses how it is calculated by considering the auxiliary space used by the algorithm in addition to the input size, which is vital for understanding an algorithm's resource usage.

💡Advantages and Disadvantages

The video script outlines the pros and cons of using algorithms. Advantages include ease of understanding, step-by-step problem-solving, and breaking down complex problems. Disadvantages include the time-consuming nature of writing algorithms and difficulty in demonstrating certain programming constructs. These points are important for providing a balanced view of the utility and limitations of algorithms.

💡Programming

Programming is the process of writing a sequence of instructions to perform specific tasks by computers. The script contrasts programming with algorithms, highlighting that while algorithms are problem-solving techniques, programming involves writing code that can be executed by a computer. This distinction is important for understanding the practical application of algorithms in computer science.

Highlights

Introduction to the concept of an algorithm and its importance in daily life and computer science.

Explanation of how an algorithm works using the real-life example of making tea.

Definition of an algorithm as a method or set of rules to perform calculations or solve problems.

Discussion on the six characteristics of an algorithm: clear and unambiguous, well-defined inputs and outputs, feasibility, finiteness, and language independence.

Clarification on the clear and unambiguous nature of algorithms, ensuring straightforward and easily readable steps.

Importance of well-defined inputs and outputs for the predictability and effectiveness of an algorithm.

Finiteness characteristic ensuring algorithms do not result in infinite loops.

Feasibility of algorithms being practical and executable with available resources.

Language independence of algorithms, allowing implementation in any programming language.

Guidance on how to write an algorithm, emphasizing flexibility and problem-solving steps.

Illustration of writing an algorithm to determine the largest number among three given numbers.

Introduction to algorithm analysis, including priori and post analysis.

Explanation of time complexity and space complexity in algorithm analysis.

Use of big O notation to express time and space complexity of algorithms.

Advantages of algorithms such as ease of understanding and step-by-step problem-solving.

Disadvantages of algorithms like time consumption and difficulty in demonstrating branching and looping.

Differentiation between algorithms and programming, highlighting their unique roles and applications.

Conclusion of the tutorial with an invitation for queries and further learning opportunities.

Transcripts

hey everyone welcome to simply learn's

youtube channel in this session we will

discuss what is an algorithm but before

we begin let me tell you guys that we

have daily updates on multiple

technologies if you're a tech geek in a

continuous hunt for latest technological

trends then consider getting subscribed

to our youtube channel and don't forget

to hit that bell icon to never miss an

update from simply done

now without further ado let's get

started with the agenda for today's

session

first we will get started with what is

an algorithm

followed by that we will look into the

characteristics of algorithm

next we will learn how to write an

algorithm

moving ahead we will look at algorithm

analysis and algorithm complexities

after that we will discuss the

advantages and disadvantages of

algorithms and finally we will see some

differences between algorithms and

programming

i hope i made myself clear with the

agenda now let's get started with the

first point that is what exactly is an

algorithm

how does algorithm work in real life

so we'll have a use case here

on my screen we have a lady and she is

shreya shreya wants to make some tea and

for that she is following some steps

so the first step is she'll take a pan

and fill it with water and place it on a

gas stove

followed by that the second step is

she'll make sure that the water comes to

a nice boil and then she adds some tea

leaves and sugar followed by step 2 we

have step 3 where she'll allow the leaf

to be fully expanded and she'll add some

milk after that

next we have the stefo where she will

wait for the tea to come for a good

decent boil

next we have step 5 where she'll turn

off the gas and she'll take the pan off

from the stove and the tea is ready to

get filtered and lastly we have the step

6 where she is all set with the tea

in computer science an algorithm is a

method or set of rules that we must be

following to perform some specific

calculations or other problem solving

operations

as a result an algorithm is a collection

of rules or instructions that govern how

a work needs to be conducted step by

step to achieve the desired results to

accomplish a task

we first provide some input and then

follow a sequence of steps to acquire

the required outcome of the input so

that is the fundamental definition of an

algorithm and we also had a use case and

now we will move ahead and understand

the characteristics of algorithms

so basically we have six characteristics

of algorithm so the first one is it

should be clear and unambiguous the

second one is that it has to be well

defined inputs and the third one is that

it has to be having well-defined outputs

as well the fourth property of an

algorithm is its feasibility followed by

that

finiteness and finally we have language

independence

now we will look into each one of the

characteristics in detail so first we

have clear and unambiguous so this

statement is the one which states that

the algorithm should be straightforward

simple and easily readable

each one of its steps should be distinct

in every way and lead it to a single

conclusion

so the next one is it should be having

well-defined inputs so this means that

an algorithm should indicate what output

can be expected as well as the input

should be properly well-defined now we

have the third one similarly we should

also have well-defined outputs so the

well-defined output characteristics of

an algorithm means that the algorithm

must clearly indicate what output can be

expected as well as the output should

also be well defined followed by the

third characteristic we have the fourth

characteristic that is the finiteness of

algorithm so the finiteness of algorithm

says that the algorithm must be finite

and it must not result in infinite loops

or similar situations

so followed by the fourth one we have

the fifth characteristic that defines

about the feasibility of an algorithm

so feasibility of an algorithm states

that the algorithm must be really simple

generic and practical

it must be able to be executed with

resources available

now the last characteristic of the

algorithm is being independent of the

language

so it means that the algorithm should be

defined in such a way that it is

completely independent of the language

it must be simple instructions that can

be implemented using any programming

language

so these were the six major

characteristics of algorithm now let's

move ahead and understand how to write

an algorithm

writing an algorithm does not have any

hard and fast rules

next algorithms are never created to

support a specific programming language

as we all know algorithm should be

capable enough to support the

conditional statements such as if if

else switch etc

an algorithm should be capable enough to

execute some of the conditional

statements such as if if else switch etc

and also it must be capable to execute

the iterative statements such as for

loop while loop do while loop etc

we usually create algorithms in a

step-by-step manner however this isn't

always the case

after the problem domain has been well

defined algorithm writing is a procedure

that is carried out

we build an algorithm to find a solution

to a problem a problem can be resolved

in a variety of ways let's look at an

example of how to write an algorithm

consider the following scenario we need

to create an algorithm to determine the

largest number among the three given

numbers x y and z as a result the

initial solution to the problem can be

written in this manner so we begin with

reading all the three numbers and in the

second step we will have a condition

that says if x is greater than y we will

proceed to step four else we will

proceed to step 5.

next in step 4 we establish a condition

that if x is greater than z then x is

the largest of the three numbers

otherwise z is the largest

if y is greater than z z will be the

greatest number otherwise y will be the

largest number amongst all the three in

step five

and the procedure will be terminated

let's have a look at what the next

solution has to offer in this algorithm

we begin by reading all the three

variables then compare all the three

numbers in the third step to determine

the largest number which is if x is

greater than y then there is another if

else statement that states that if x is

greater than y then x is largest

otherwise z is the largest

then this if else statement which says

that if y is greater than z then y is

greater otherwise z is the greatest of

the three numbers so this is how we have

multiple solutions to the same problem

so after discussing these solutions we

will move ahead and understand algorithm

analysis

the algorithm may be studied in two

levels first before it is made and then

after it is created the two analysis of

an algorithm are as follows the first

one is priori analysis and the second

one is the post analysis so first we

will talk about the priori analysis

priori analysis refers to the

theoretical analysis of an algorithm

performed before its implementation

before implementing the algorithm other

parameters such as processor speed might

be considered

which does not affect the implementation

component next we will talk about post

analysis

a practical analysis of an algorithm is

called as posterior analysis and it

utilizes any computer language to build

the algorithm the purpose of this

analysis is to determine how much time

and space the algorithm takes to operate

now after being understood the algorithm

analysis we will be able to comprehend

the algorithm complexity two methods can

be used to assess the algorithm

complexity the first one is time

complexity which states that the amount

of time required to finish an

algorithm's execution is known as its

time complexity

followed by time complexity the other

one is the space complexity which is

calculated by the quantity of space

required to solve a problem and produce

an output of space complexity of an

algorithm

let's take a closer look at these

complexities

now we will begin with time complexity

of an algorithm the big o notation is

used to express an algorithm's time

complexity the asymptomatic notation is

used to depict temporary complexity of

big o notation

the time complexity is mainly determined

by counting the number of steps required

to complete the task

let's take a look at an example to

understand this time complexity in a

much better way

if we want to find out a multiplication

of n numbers we can do it by executing a

loop from 1 to n then calculating

multiplication when the loop ends then

multiplication holds the n numbers

multiplication and last we return the

calculated multiplication

the loop statements time complexity will

be at least n and when the number of n

increases the time complexity will also

increase

while the code's complexity that is

returns multiplication will remain

constant because its value is unaffected

by the value of n and it will obtain the

result in every single step

next we will discuss about space

complexity which is expressed with big o

notation just as time complexity

these four items are stored in space

complexity it initially saves program

instructions then stores constant values

then stores variable values and finally

it keeps track of function cells jumping

statements and so on the sum of

auxiliary space and input size is used

to calculate space complexity the extra

space or temporary space used by an

algorithm is referred to an auxiliary

space after learning about algorithm

complexity we will look at some of the

algorithms pros and cons so let's start

with the advantages of algorithms

firstly algorithms are easy to

understand

next algorithms are step-by-step

representation of a solution and lastly

the problem is broken down into smaller

bits or steps in an algorithm making it

easier for the programmer now an

algorithm also have various drawbacks

one of which being it takes long time to

write hence it is time consuming

second con of the algorithm is

algorithms make it harder to demonstrate

branching and looping statements

so followed by the advantages and

disadvantages of algorithms we now enter

into the final segment where we discuss

the differences between algorithms and

programming so the first difference is

that

an algorithm is a type of programming on

the other hand a program is more

directly associated with the computer

performing one or more tasks but an

algorithm is more of a notation a

technique for solving a problem

now let us discuss the second difference

an algorithm can be decoded or run by a

human whereas the program is only run or

decoded by a set of compilers of the

computer

now the third difference

basically an algorithm is a design of

the solution to the problem

here we can only analyze the solution

but we can never run it

but whereas on the other hand

programming is completely a different

ballgame here you can directly implement

a certain phase or an entire program and

test the programs and get an output

so the fourth and the last difference

between an algorithm and programming is

an algorithm is written using natural

human vocabulary

whereas programs are written using any

programming language such as c c plus

plus java python etc

now with that we have come to an end of

this tutorial on what is an algorithm if

you have any queries regarding the

topics covered in this session then

please feel free to let us know in the

comment section below and our team of

experts will be happy to resolve all

your queries until next time thank you

stay safe and keep learning

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