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hey everyone welcome to simply learn's
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youtube channel in this session we will
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discuss what is an algorithm but before
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now without further ado let's get
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started with the agenda for today's
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session
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first we will get started with what is
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an algorithm
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followed by that we will look into the
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characteristics of algorithm
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next we will learn how to write an
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algorithm
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moving ahead we will look at algorithm
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analysis and algorithm complexities
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after that we will discuss the
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advantages and disadvantages of
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algorithms and finally we will see some
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differences between algorithms and
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programming
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i hope i made myself clear with the
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agenda now let's get started with the
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first point that is what exactly is an
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algorithm
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how does algorithm work in real life
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so we'll have a use case here
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on my screen we have a lady and she is
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shreya shreya wants to make some tea and
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for that she is following some steps
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so the first step is she'll take a pan
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and fill it with water and place it on a
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gas stove
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followed by that the second step is
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she'll make sure that the water comes to
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a nice boil and then she adds some tea
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leaves and sugar followed by step 2 we
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have step 3 where she'll allow the leaf
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to be fully expanded and she'll add some
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milk after that
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next we have the stefo where she will
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wait for the tea to come for a good
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decent boil
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next we have step 5 where she'll turn
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off the gas and she'll take the pan off
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from the stove and the tea is ready to
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get filtered and lastly we have the step
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6 where she is all set with the tea
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in computer science an algorithm is a
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method or set of rules that we must be
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following to perform some specific
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calculations or other problem solving
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operations
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as a result an algorithm is a collection
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of rules or instructions that govern how
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a work needs to be conducted step by
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step to achieve the desired results to
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accomplish a task
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we first provide some input and then
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follow a sequence of steps to acquire
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the required outcome of the input so
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that is the fundamental definition of an
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algorithm and we also had a use case and
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now we will move ahead and understand
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the characteristics of algorithms
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so basically we have six characteristics
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of algorithm so the first one is it
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should be clear and unambiguous the
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second one is that it has to be well
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defined inputs and the third one is that
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it has to be having well-defined outputs
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as well the fourth property of an
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algorithm is its feasibility followed by
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that
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finiteness and finally we have language
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independence
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now we will look into each one of the
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characteristics in detail so first we
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have clear and unambiguous so this
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statement is the one which states that
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the algorithm should be straightforward
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simple and easily readable
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each one of its steps should be distinct
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in every way and lead it to a single
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conclusion
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so the next one is it should be having
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well-defined inputs so this means that
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an algorithm should indicate what output
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can be expected as well as the input
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should be properly well-defined now we
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have the third one similarly we should
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also have well-defined outputs so the
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well-defined output characteristics of
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an algorithm means that the algorithm
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must clearly indicate what output can be
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expected as well as the output should
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also be well defined followed by the
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third characteristic we have the fourth
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characteristic that is the finiteness of
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algorithm so the finiteness of algorithm
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says that the algorithm must be finite
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and it must not result in infinite loops
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or similar situations
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so followed by the fourth one we have
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the fifth characteristic that defines
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about the feasibility of an algorithm
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so feasibility of an algorithm states
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that the algorithm must be really simple
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generic and practical
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it must be able to be executed with
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resources available
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now the last characteristic of the
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algorithm is being independent of the
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language
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so it means that the algorithm should be
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defined in such a way that it is
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completely independent of the language
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it must be simple instructions that can
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be implemented using any programming
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language
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so these were the six major
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characteristics of algorithm now let's
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move ahead and understand how to write
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an algorithm
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writing an algorithm does not have any
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hard and fast rules
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next algorithms are never created to
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support a specific programming language
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as we all know algorithm should be
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capable enough to support the
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conditional statements such as if if
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else switch etc
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an algorithm should be capable enough to
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execute some of the conditional
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statements such as if if else switch etc
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and also it must be capable to execute
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the iterative statements such as for
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loop while loop do while loop etc
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we usually create algorithms in a
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step-by-step manner however this isn't
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always the case
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after the problem domain has been well
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defined algorithm writing is a procedure
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that is carried out
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we build an algorithm to find a solution
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to a problem a problem can be resolved
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in a variety of ways let's look at an
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example of how to write an algorithm
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consider the following scenario we need
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to create an algorithm to determine the
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largest number among the three given
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numbers x y and z as a result the
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initial solution to the problem can be
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written in this manner so we begin with
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reading all the three numbers and in the
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second step we will have a condition
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that says if x is greater than y we will
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proceed to step four else we will
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proceed to step 5.
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next in step 4 we establish a condition
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that if x is greater than z then x is
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the largest of the three numbers
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otherwise z is the largest
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if y is greater than z z will be the
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greatest number otherwise y will be the
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largest number amongst all the three in
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step five
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and the procedure will be terminated
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let's have a look at what the next
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solution has to offer in this algorithm
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we begin by reading all the three
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variables then compare all the three
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numbers in the third step to determine
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the largest number which is if x is
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greater than y then there is another if
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else statement that states that if x is
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greater than y then x is largest
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otherwise z is the largest
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then this if else statement which says
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that if y is greater than z then y is
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greater otherwise z is the greatest of
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the three numbers so this is how we have
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multiple solutions to the same problem
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so after discussing these solutions we
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will move ahead and understand algorithm
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analysis
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the algorithm may be studied in two
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levels first before it is made and then
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after it is created the two analysis of
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an algorithm are as follows the first
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one is priori analysis and the second
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one is the post analysis so first we
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will talk about the priori analysis
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priori analysis refers to the
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theoretical analysis of an algorithm
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performed before its implementation
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before implementing the algorithm other
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parameters such as processor speed might
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be considered
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which does not affect the implementation
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component next we will talk about post
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analysis
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a practical analysis of an algorithm is
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called as posterior analysis and it
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utilizes any computer language to build
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the algorithm the purpose of this
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analysis is to determine how much time
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and space the algorithm takes to operate
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now after being understood the algorithm
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analysis we will be able to comprehend
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the algorithm complexity two methods can
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be used to assess the algorithm
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complexity the first one is time
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complexity which states that the amount
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of time required to finish an
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algorithm's execution is known as its
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time complexity
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followed by time complexity the other
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one is the space complexity which is
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calculated by the quantity of space
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required to solve a problem and produce
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an output of space complexity of an
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algorithm
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let's take a closer look at these
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complexities
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now we will begin with time complexity
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of an algorithm the big o notation is
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used to express an algorithm's time
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complexity the asymptomatic notation is
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used to depict temporary complexity of
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big o notation
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the time complexity is mainly determined
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by counting the number of steps required
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to complete the task
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let's take a look at an example to
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understand this time complexity in a
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much better way
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if we want to find out a multiplication
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of n numbers we can do it by executing a
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loop from 1 to n then calculating
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multiplication when the loop ends then
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multiplication holds the n numbers
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multiplication and last we return the
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calculated multiplication
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the loop statements time complexity will
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be at least n and when the number of n
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increases the time complexity will also
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increase
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while the code's complexity that is
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returns multiplication will remain
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constant because its value is unaffected
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by the value of n and it will obtain the
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result in every single step
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next we will discuss about space
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complexity which is expressed with big o
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notation just as time complexity
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these four items are stored in space
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complexity it initially saves program
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instructions then stores constant values
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then stores variable values and finally
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it keeps track of function cells jumping
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statements and so on the sum of
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auxiliary space and input size is used
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to calculate space complexity the extra
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space or temporary space used by an
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algorithm is referred to an auxiliary
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space after learning about algorithm
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complexity we will look at some of the
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algorithms pros and cons so let's start
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with the advantages of algorithms
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firstly algorithms are easy to
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understand
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next algorithms are step-by-step
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representation of a solution and lastly
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the problem is broken down into smaller
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bits or steps in an algorithm making it
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easier for the programmer now an
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algorithm also have various drawbacks
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one of which being it takes long time to
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write hence it is time consuming
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second con of the algorithm is
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algorithms make it harder to demonstrate
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branching and looping statements
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so followed by the advantages and
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disadvantages of algorithms we now enter
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into the final segment where we discuss
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the differences between algorithms and
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programming so the first difference is
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that
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an algorithm is a type of programming on
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the other hand a program is more
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directly associated with the computer
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performing one or more tasks but an
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algorithm is more of a notation a
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technique for solving a problem
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now let us discuss the second difference
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an algorithm can be decoded or run by a
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human whereas the program is only run or
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decoded by a set of compilers of the
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computer
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now the third difference
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basically an algorithm is a design of
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the solution to the problem
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here we can only analyze the solution
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but we can never run it
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but whereas on the other hand
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programming is completely a different
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ballgame here you can directly implement
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a certain phase or an entire program and
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test the programs and get an output
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so the fourth and the last difference
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between an algorithm and programming is
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an algorithm is written using natural
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human vocabulary
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whereas programs are written using any
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programming language such as c c plus
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plus java python etc
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now with that we have come to an end of
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this tutorial on what is an algorithm if
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you have any queries regarding the
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topics covered in this session then
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please feel free to let us know in the
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comment section below and our team of
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experts will be happy to resolve all
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your queries until next time thank you
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stay safe and keep learning
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