DSA is a cryptographic algorithm used to generate digital signatures, authenticate the sender of a digital message, and prevent message tampering. DSA works by having two keys: a private key owned by the sender and a public key held by the receiver.
C++ Basics in One Shot - Strivers A2Z DSA Course - L1
This is a full-fledged interview preparation website that I run on my end so if you 're someone who has
three months to like six months of time left for interviews I will definitely ask you how to check this
Strivers SD sheet. This is one of the most followed resources in the country as of now what does this
resource gives you it gives you 119 well curated problems such that all your DS algo Concepts will be
covered. You should definitely check out coding ninjas because web development okay data Stitch
algorithm foreign County there 's a link in the description make sure you check them out I 'll be using
vs code in order to code I'll be writing my C plus plus code over here and whatever the code generates
as an output will be produced over here. In the next video we will be covering Java 1. C plus plus we
can use the hash include so hash include i o stream imagine if you want to use something like a math
dot h I 'll be talking about radical functions afterwards. C out is a function which exists under the STD
and double colon so in order to use C out you have to write STD.
Program always uses STD for all the functions for most of the functions you have to write STD double
colon double Corner. If you compile it prints everything now it looks a easier task is n't it so this is how
you can easily write okay now let 's quickly have an input imagine you want to take an input. It's going
to take you a lot of time this is where C plus plus C is a I 've got something better for you I say can I
write bits STD C plus Plus C plusplus C. It includes all the libraries everything whatever libraries are
there in C plus. plus plus. everything is included under this bits slash stdc pluscplus plus dot h. We will
be specifically using two data types float and double again they have ranges depending on the Range
that you use you 'll be using float or double the ranges are visible on the screen. If you want to store
bigger numbers than this this is where something like long long will come in so if you are saying long
long it will give you a wider range.
If we use something like get line inside the get line you have to write CN what is get line again do not
need to dig deep it's an internal function. The moment you click enter the next line will not be picked
up so it just picks up till the line break so string and get line is used to take any of the string. Character
can store all of the 256 characters in English dictionary. If we have something like a 10 and that 10 can
be stored in all the three or all the five why ca n't we use simply long long or maybe double?
Everything takes up a certain space in your computer so depending on that we decide what to use now
integer has a range now those numbers you can't uh remember so what I usually do is I keep a
rounding of number like I know integer will be from minus 10 to the power 9 to 10 to power 9. If you
are greater than equal to 18 then I can say you are an adult you're an adult yes or if you are lesser
than 18 E1 not an adult. If you omit the else statement what will happen is the 15 will be taken as the
input and the if will not be executed and will not find an else.
The problem is very simple school has following rules for grading system below 25 grade f 25 to 44
grade e 45 to 40 49 ready and so on so your task is to ask user to enter marks and print the
corresponding grade okay so what is the first reading get the marks. Backslash asterisk is how you can
do it a single line. If 24 is true over here none of these lines will be executed because it states else it
will never go there and it will not be executed so you 'll be saving a lot of time previously in every F
was executed so this is why else if will be written now another thing you 're having 24. marks is going
and checking this set imagine the marks are something like 86. If the age is smaller than 18 you can
print this and all the conditions are given to you so something we know uh for sure is we need age
right so we can take the scene of H now we know something if H is uh smaller than H then we got ta
print something like not eligible per job. If it is greater than equal to 18 you will be printing eligible for
job. But if it is between 55 and 57 eligible for the job but retirement soon that is what you have to print
got it right.
, Time and Space Complexity - Strivers A2Z DSA Course
This is the continuation of Strivers A to Z DSA course slash cheat so uh if you remember in the
previous video we have covered all of these green TIG Mark things. This video will be covering the time
complexity learn Basics and then analyze the next steps. Eventually when you complete all the steps
or all the problems you will have a very very good hold on time complexity. Time complexity can not
be said as time taken because it is dependent on system it is different dependent on configuration
right so this is why that is this is the first point time taken is never equal to time taken. Time
complexity is what you call As Time complexity depending on the input if they are giving you more
input it might end up taking a certain more time so the rate at which the time increases is what is
generically referred as time complexity. Raj explains how to compute the time complexity or the Big O
of a piece of code. Raj says that in all the interviews that you're going to give or all the examinations if
you 're writing a code they will ask you to analyze the time that is when you do not like you will not say
two seconds no you will say it in terms of bigon notation.
There are three things that have written always compute time complexity in terms of worst case
scenario. One is the best case, the average case and the other one is the worst case. what you write
and this is time complexity it runs for 15 times but this is a number this is not a number you generally
do not represent your code. Always yes always compute the time complexity in terms of worst case
scenario. The average case is the best plus worse and divided by two it's it 's the median of it so self-
explanatory if you 're building a system will you build it for one person or or will you. you say that your
code runs in week of four obviously you will say we go for because that might be the worst case that
the computer might encounter when it is given an input. Beagle notation is what you will be expressing
your code in interviews. Avoid constants because whenever the input size is very large those constants
have very less significance. Avoid lower values which does not change its significance by much so
avoid lower values correct. Bigo notation is always the highest complex or the worst case complexity.
You'll find different teachers on YouTube if you are learning from me you 're learning for interviews for
coding rounds for problem solving abilities not for your semester exam so please do not comment that
you did not teach the mathematical derivation because that is not required while problem solving right
so you know how to compute picona. for n n every time it is running for n and n so can I say it 's
running for exactly n times how many times is it running so we go off n square is what is the time
complexity of this particular let 's say the next example and try to compute the time. complexity. of
this one so it is the number of iterations it is taking again I 'm taking the overall iterations now first.
first time is one equation next time 2 x m is 3 and X7 is 4 so on Del Nitric. Time complexity is the
memory space that your program takes in a very very naive term when I talk about memory space
again it will vary from machine to machine so you can not be dependent on the machine and that is
why again in order to complete base complexity we will be using the bigo notation again. Space
complexity is nothing but auxiliary space Plus input space.
If you use any extra variable or extra space to solve the problem that is what you refer as auxiliary
space and combined I can say this is the space complexity. In an interview you will have to say it in
terms of bigo of something not bytes KB MB so for example if I Define an array of size n it means I 'm
consuming B go of n size or n space complexity so in an interview. The more problems you solve the
space complexity gets into your head in a much much better way so before ending up this lecture in
case you are into competitive programming then remember one thing over there you do not run your
codes on your MacBook or your windows whatever code you write you send it to the server. Remember
that most of the servers most of us are take one second for roughly 10 to the power 8 operations. The
next lecture will
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