Is a number Prime? - Solution | Java Foundation Course | Lecture 11

Question Name:
Is a number Prime?
Question Link:
Question Statement:
1. You've to check whether a given number is prime or not.
2. Take a number "t" as input representing count of input numbers to be tested.
3. Take a number "n" as input "t" number of times.
4. For each input value of n, print "prime" if the number is prime and "not prime" otherwise.
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NADOS also enables doubt support, career opportunities and contests besides free of charge content for learning. In this video, we discuss the solution of "Is a number Prime" problem. To understand the question, watch this video: • Is a number Prime? - Q...
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Hashtags
#java #javafoundation #isnumberaprime

[@naushadalam5129]

🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂🙂first time in life , maine real example ke sath time complexity smjh liya sir .aaj tak sirf books me hi pdhe the sir 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏 thank you sir ......you are great 🤟

[@mdzahidfaran7743]

What an explanation. I have not seen this type of explanation on any other Java tutorial.

[@akshatapawar32]

Best mentor ever.Thank you summit sir you are preparing us to think in all direction of problems with considering time complexity of questions.Thank you so much.

[@Pepcoding]

It's my pleasure

[@bishalkeshri2168]

Very truly said, he's the best mentor a student can ever have. Such a humble and down to earth celebrity he is❤❤🙏🙏.

[@sarthaknikhal5540]

Sir, please make videos on how to find time complexity. It's a humble request. I really understand your explanations, and that's the reason for this request. Thank you!

[@Pepcoding]

beta ab se kisi question mei miss nahi hogi. level2 se

[@sarthaknikhal5540]

@@Pepcoding ok, sir 👍

[@aakankshajha2080]

import java.util.*; public class Main{ public static void main(String[] args){ Scanner sc=new Scanner(System.in); int t=sc.nextInt(); for(int i=1;i

[@sportsdata5018]

Can I connect with you on LinkedIn?

[@poojachoudhary4607]

How you get to know that T will do operations of 10 to the power 4 exactly ?

[@nustagame25]

Problem statement

[@shubhamaggarwal3823]

i loved the way u solved the question in pieces ....😍😍

[@MadaraUchiha1706_]

If you guys starts loop from 2 then you should update if block(outside loop one) with if(sum==1) because if we are starting loop from 2 then sum value should only be increased 1 time because of itself...

[@rahul_singh_rajput3292]

I'll follow this dsa courSe 🙂🙂 the best way of teaching and explaining here 🙃 i ❤ it.. Pepcoding 😊😊

[@Pepcoding]

Glad you love the explanation, for better experience and well organised content sign up on nados.io and start learning.

[@SCRIPTSAG]

Sir es tarike se socha nhi kabhi pahli bar lag rha hai ki coding hoti kya hai

[@techeduidea2598]

Sir kuch set of question ka practice kara dijiye Time and Space Complexity par please

[@AsmitaRana-qj3li]

Amazing ..sir .. You are the best

[@ujjawalgupta98]

sir i am solving this question at the website currently with your exact solution..still it is showing 6/10

[@Pepcoding]

Beta, question dhng se pdo aur jo question main print krne k liye given h usse as it is print krna h.

[@ishantsadhawani350]

@@Pepcoding Sir I am still facing the issue 2/5 test cases failed.(Runtime Error).

[@shivam3387]

@@Pepcoding Sir, test cases me 10 ko as a prime print karne bola rha

[@ishantsadhawani350]

@@Pepcoding Sir please help.🙌

[@ankushgupta365]

try this code... import java.util.*; public class Main{ public static void main(String[] args) { Scanner scn = new Scanner(System.in); int t = scn.nextInt(); for(int i = 0; i < t; i++){ int n = scn.nextInt(); int div = 2; while(div * div n){ System.out.println("prime"); } else { System.out.println("not prime"); } } } }

[@RobbyDongre]

Sir suppose if we are checking for number "1" . Answer prime ayga is approach see . Any solution for that ?

[@Rohit-te9dr]

Thank you summit sir you are preparing us to think in all direction of problems with considering time complexity of questions.Thank you so much. but sir their is a small mistake in your program it gives 0 and 1 as prime

[@Pepcoding]

I am glad

[@manish4275]

Sir square root method ka Time complexity O(n) hai ki O(sqrt(n))? Also Sir, if our input number (n) is very very large, like 10 ^ 20, will the same code work? Assuming we used long long int or double.

[@Pepcoding]

This won't work for very large numbers. You will have to use Java Long. Complexity square root n ki hai.

[@Dibakash]

Hi, you have not set a guard clause (for n == 0 or n == 1). The portal (pepcode) is accepting wrong codes that wrongly output 1 as prime. And it is rejecting correct codes. The failed test cases clearly show that for the input int 1, it is expecting output as prime (which is wrong as 1 isn't a prime number)

[@Dibakash]

However, thanks for the wonderful concepts (specially the recursion series)

[@Farhan-uo2ll]

❤️❤️thnku so much sir

[@yubarajmohanty70]

thank you sir

[@lakshmipunugula2274]

sir,can you please explain in english.

[@himanshuaggarwal2445]

sir you teach best i loved it 👍

[@Pepcoding]

I am glad you liked it. I also hope that you are watching till end and trying to understand the what, how and especially why of the problem. If you like my efforts, I request a review g.page/Pepcoding/review?rc

[@rohanrohan2758]

If n=12, then count will increase as '1' ie count = 1. then how will the count will restore to '0' for the next input? Please answer.

[@daaamn6414]

Lol now I am also confused after reading this. Can you please explain the answer if u found it ?

[@princetirkey8710]

Also if the number is 1 then also it is printing "Prime" but we know 1 is "not prime"

[@princetirkey8710]

@@daaamn6414 After the internal loop terminate the count variable gets destroyed as it is local variable to external i loop , after this i++ a new count variable is created with count =0

[@daaamn6414]

@@princetirkey8710 Yeah thnx bro! Got it !!

[@manikasunal7687]

You are one of the best teacher 🙌

[@Pepcoding]

Wow, thank you!

[@StudyWithAnupam]

What is the use of Int Count ?

[@simarjeetsingh6531]

+1

[@shivamsetia4711]

Can anyone explain how this code is working for number 15

[@umang2049]

Toh maine aapki prime no. Ki video dekhi or aage bhi follow kr rha hu toh sir kabse khud sa bnana aana chaiya ya aajaega?

[@Pepcoding]

Level 1 to yunhee niklega

[@ojasgupta1189]

Great sir !!!!

[@th3graduate292]

it took time but i understood it very well.

[@thiyageshkanna]

Would be better if you teach in english!!!

[@gokul6120]

Sir aap count kyo use kiye.

[@Pepcoding]

bhot sare tareeke hain. ye bhi to theik hai.

[@RohitGupta-kl7je]

I run the same program it's saying for n .. Variable declaration is not allowed here

[@rohitsorot5136]

mne kal placement program wale batch me samja ye question but ab jake full clear hua app abhi bhi best pada rahe ho sumeet sir dont stop teaching please i want to study level 2 and 3 from you atleast if u dont have time make level 2 3 videos so i cant clear doubt in class i will saw the vides pleasse its a request i know sab teacher bht accha content bana rahe h bbut jse ape level 1 dal rakha h ese hi level 2 3 bhi slow and steady bana dijiye jara compare karo views ke apke content pe views kitne aate h....ese bh teachers h jinhone coaching centre khol liye but still vo khud bhi padate h

[@pratikdeore7427]

Very helpful explanation :)

[@KishanYadav-fn1gl]

(√n) root nka concept nhi samja koi explain kar do

[@NoOne-jl2ii]

12 / 554

[@rajdipdas1329]

for the number 24 if we proceed with normal process then 2*12 and 12*2 is the same thing then why should we check so many times there is the huge wastage of time for that reason we have to go upto sqrt(n).

[@Pepcoding]

For better insight, visit nados.io, post your doubts, community will help you out there.

[@snehasomnathe8802]

Best Explanation, I have ever seen

[@RaviVerma-pm6bx]

You missed part when user entered one of the input number as 1 then this code will not show proper output. I think If(i!=1) outside your inner for loop is required.

[@Pepcoding]

1 is neither prime, nor composite. Hanji, alag se handle karna chaie tha.

[@manishkumarprasad1911]

you are right. but I think you don't see the constraints in the question that is (2

[@travel2react567]

Best problem solving approach. aise to aaj tak kisi ne programming nahi samjhaya.

[@umang2049]

Sir abhi khud sa code nhi bn pa rha

[@Pepcoding]

Beta ye to shuru hai. Thode time baad bna paoge

[@adityarenapure7397]

sir where is our academy??

[@Pepcoding]

pitampura, delhi

[@prathamdhiman764]

Sir u didn't told us earlier about count and div

[@Japanpreet]

I didn't get it

[@geetanegi2736]

Sir level 1 ka lia notes bnana jruri hai kya???????🇮🇳🔥😎🇮🇳

[@Pepcoding]

nhi to

[@waseemqureshi3607]

sir isme t kya krr rha hai

[@bentennyson8923]

sir, please correct the test cases for this question.

[@mr.nobody8365]

*Completed*

[@rock_213]

Thank you so much sir❤

[@nightcrusader5047]

Damn good explanation sir

[@brajesh2334]

sir if input will be 1 then how to tackle it

[@Pepcoding]

For such queries sign up on nados.io and you can post your queries on community section of NADOS.

[@shubhamaggarwal3823]

thank you sir 🙏🙏👍👍

[@vedanthbaliga7686]

Is this the sieve of eratosthenes algorithm?

[@Pepcoding]

Nope. But this is also optimizes somewhat.

[@bhanupratapsingh5468]

Sumit Sir do you teach Python also?

[@Pepcoding]

Not now but we will cover it soon.

[@deepakgauttam29]

Sir n=1 per work nhi kar rha

[@stayuptodate6441]

just modify the condition as if (count == 0 && n!=1)

[@yashkaushik8691]

thanks soo much sir

[@Pepcoding]

Most welcome Beta and If you like our efforts, please upvote the comments written by the students about Pepcoding here (www.quora.com/What-are-the-good-websites-to-learn-data-structures-and-algorithms )

[@yashgarg3373]

I Learned a new way to solve it... thank you sir..

[@Pepcoding]

Most welcome

[@realigc8778]

Sir jab m coding vs code m kar rha tha toh usne scn ko close karne k liye bhi kha ... Esa kya ??

[@Pepcoding]

Beta, I regret to inform you that, I won't be able to answer/solve the personal doubts of each and every student over here. For clearing your doubts, you can join our community on telegram - t.me/pepcoding.