The DSA works in the framework of public-key cryptosystems and is based on the algebraic properties of modular exponentiation, together with the discrete logarithm problem, which is considered to be computationally intractable. The algorithm uses a key pair consisting of a public key and a private ...
Lecture 1: Intro to Programming & Flowcharts
Introduction
Hello everyone!Today, we will be starting our DSA course and in this lecture, we will be
discussing flow charts, pseudocode, and programming languages. We will also talk about the
importance of using them. If you already have knowledge about these topics, feel free to skip
ahead.
Getting Started with DSA
If you are new to programming, grab a pen and paper and let's dive in! The intent of this course
is to prepare you to easily solve any DSA question that comes up in online tests or interviews.
You should be able to provide optimal solutions to these problems.
Problem:
Given a set of values, how do we approach the problem and write code to solve it?
Solution:
Analyze the problem: Before writing any code, it's important to understand the problem and
break it down into smaller, manageable parts. This involves identifying the inputs and expected
outputs, as well as any constraints or requirements.
Choose an appropriate algorithm: Once we have a clear understanding of the problem, we can
choose an algorithm that fits our requirements. This may involve researching different
algorithms and their time and space complexities.
Write pseudocode: Before writing actual code, it's useful to write out the steps we need to take
in plain English. This helps us to organize our thoughts and ensure that we are on the right track
before we start coding.
Write code: Finally, we can write the actual code to solve the problem. This may involve
debugging and testing to ensure that the code works as expected.
Example code:
def example_function(input): # Step 1: Analyze the problem # Identify inputs and expected
outputs # Consider any constraints or requirements # Step 2: Choose an appropriate
algorithm # Research different algorithms and their complexities # Step 3: Write
pseudocode # Break problem down into smaller steps # Organize thoughts and ensure on
right track # Step 4: Write code # Solve problem using chosen algorithm # Debug and
test code return output
Here's a problem and its solution:
First, we'll come up with a rough solution using pseudocode or a flowchart.
Then, we'll write the actual code for it using a high-level language.
However, computers only understand 0s and 1s, so we need to convert our code into a
machine-readable format.
Once we do that, our program becomes executable.
,For example, if we wrote a program to add a+b and want to print the answer, we need to make
sure it's in a format the computer can understand.
To make the computer understand the given problem, we need to convert it into machine
understandable language. The process involves:
Formulating the first question
Providing the necessary values
Deciding on the approach
Coding the solution
Once we have written the code, we need to ensure that it is in a format that the computer can
understand.
Understanding Source Code and Flow Charts
Source code refers to the instructions written in a specific programming language that a
computer can understand and execute. It's the backbone of any software or application.
A flow chart, on the other hand, is a diagrammatic representation of an approach to solving a
problem. It breaks down the approach into various components that can be easily understood
and followed.
So, when we write source code, we are essentially writing instructions for the computer to follow.
And when we create a flow chart, we are breaking down those instructions into a visual
representation that can be easily understood by humans.
Lecture 2: Write Your First Program in C++
Hello ji, How Are You?
This is the 2nd lecture of our DSA series. Today we are going to create our first program. We
will see how a program runs and what does each line mean. We are going to understand
everything in this lecture. So let's get started.
Getting Started
We saw in the last lecture that we create our source code using a programming language. But
we know that a computer won't understand our code because it only knows binary (01)
language. So, we need something that translates our source code into machine understandable
language just like we use a translator to convert Hindi to French.
We have a compiler which converts source code into binary language, allowing it to be run by a
computer and produce an output. This is how the compilation process works. Essentially, the
compiler makes it possible for us to run a source code.
Here's an example: let's say we have a=1, b=2, and we want to do c=a+b. The computer won't
be able to understand these lines of code on its own. First, a compiler converts the source code
into an executable format, which the computer can then run.
,So, to summarize: a program works by using a compiler to convert source code into an
executable format that can be run by a computer and produce an output. Hopefully, this gives
you a basic understanding of what a compiler does and how a program is executed.
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Compiler: Conversion and Error Detection
The compiler handles two main functions:
Translation of code
Error detection
, During compilation, the compiler checks for any errors in the code, both at compile time and
during runtime. This allows you to identify and correct any issues before executing the code.
Therefore, the main uses of the compiler are conversion and error detection.
Now, let's dive into our first program.
Lecture 3: If-Else, While loop & Lots of Patterns (Part-1)
Hello there, how are you doing?
So far, we have covered a lot of ground, including creating our first program and understanding
operators.
Pseudocode
Pseudocode is a type of code that is written in plain English to help programmers plan and
design their programs before they start coding. It is a high-level description of the steps that a
program will take to solve a problem.
Example:
1. Set a variable called num to 0
2. Ask the user to input a number
3. Add the input number to num
4. Repeat steps 2 and 3 four more times
5. Display the value of num
Flowchart
A flowchart is a diagram that shows the steps of a process. It uses symbols to show the different
stages of the process and how they are connected.
Example:
Flowchart
Data Types
Data types are used to define the type of data that a variable can hold. They are important
because they determine what operations can be performed on the data.
Integer: used for whole numbers
Float: used for decimal numbers
Boolean: used for true or false values
String: used for text
Array: used for a collection of data
Compilation Process
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