Reminder this is who gets to decide if you have a job.
Reminder this is who gets to decide if you have a job
Noah Taylor
Lucas Robinson
>35 is a prime number
Joshua Kelly
for prime numbers you have to check if its even
if not then from 3 to sqrt(NUM) check every other number whether NUM is divisible by it
and remember to only check for NUM that is a neighbour of a number that is divisible by 6, because that's where primes are
hope that helps
Carson Flores
think you meant 25, brainlet
John Johnson
holy shit, is that, dare I say, the most efficient way of computing prime numbers?
Jaxson Jackson
he would be correct if he added 5 and 7 btw
Colton Edwards
but he didn't
Ethan Taylor
121
Ryder Thomas
John Martin
You check if a number is even by checking if its %2 == 0, which is what you're doing anyway with the other integers. So just check if it's divisible by every integer between 2 and floor(sqrt(num)). It does the same, but it's easier to explain.
Joshua Smith
>if a candidate couldn't write the logic to determine if a number is prime or not... that's another red flag
Hudson Long
what's bad about only wanting to hire people who know basic math?
Carson Bailey
Are you being coy, because it seems like you missed what's funny about it...
Josiah Walker
I get the image is laughing at the reddit poster but OP seems like he thinks asking this question is unjustified
Robert Williams
Alexander Hall
am I missing the point or do you also think that expecting someone to know high school level math is unreasonable?
John Roberts
have you ever programmed anything, you would know why it's funny
John Myers
What if that's not what OP is implying? What if it's actually that the guy in the picture just got it fucking wrong, yet he's the one in control of the interview questions and that's what's fucked up about it.
Jaxson Rivera
More than 100, so it's behind the scope. I agree it's useful to check for square root and cube root, but for numbers less than 100? Seems redundant.
Austin Jones
>he thinks 25 is a prime number
Anthony Flores
>interviewer says not knowing how to write an is_prime() function is a "red flag"
>interviewer doesn't know how to write an is_prime() function and thinks its a trivial problem similar to solving fizzbuzz (its not).
Brody Lewis
the funny thing is that I've had this happen on an interview, there was an older guy and a tryhard junior doing the interview and the guy tied to correct me so I pointed out he was wrong too
guy turned red as a tomato, I couldn't hide my smirk at this time, you could tell he was about to die of embarrassment as I was showing him what he did wrong
Nicholas Fisher
It is trivial. Making it more efficient is a bit "tricky", but when time and space complexity are not important it is very easy.
Well i guess you didn't get the job?
Cameron Baker
I got called back but I did like 30 interviews that month and got a much better offer at a different company. It's not that big of a deal, the question was ridiculously hard and the older guy knew it, and as long as you can show that you are not "stuck" completely it's not really a problem which I obviously demonstrated by BTFO this little shithead that was with him.
Still one of the the most hilarious moments in my life, he was so fucking red I will never forget it, totally worth it just sitting there with a smirk on my face
Ethan Green
>reddit
That's Hacker News
James Gray
>falling for this obvious bait
Aaron Ward
number theorists BTFO by random recruiter
Asher Harris
>It is trivial. Making it more efficient is a bit "tricky", but when time and space complexity are not important it is very easy.
And this assclown, who judges others' competence, failed to do it.
Austin White
That recruiter obviously has a pole up his ass with a red flag dangling on it. How the fuck don't you know how to figure out if a number is prime or not.
Eli Collins
so
Dylan Barnes
I meant something like this
Adrian Gutierrez
[spoiler] BTFO [/spoiler]
Jason Stewart
Jace Butler
I see nothing wrong.
Brandon Harris
t. smtddr
Christian Moore
who the fuck works for a company in 2019 this is why you people will never account to anything, work for yourselves you stupid cucks
Luis Wright
I'm so appreciative of the pseudo-anonymous nature of imageboards, All the megabrainlet posts I've ever made (including one just earlier today) won't immortalized in a forum somewhere, and even if they're archive by a third party, can't be tied back to me.
Camden Thomas
>never account to anything
neither will you
Jayden Campbell
>most tech people people are hyper-logical cold-hearted emotionless sociopaths
Jacob Turner
Show me a composite number that can be divided by 2 or 3 with a natural number as the result, then.
Brayden Young
6
Easton James
25
Parker Wilson
>tfw you're not landing a job in tech because you're not hyper-logical, cold-hearted, and emotionless
god damn it
Robert Hall
I wrote composite instead of prime, try again.
Jace Ward
You only have to check factors that are themselves prime, so if you're counting primes starting at 2, you can use the primes you've already determined in order to check the later ones. also, calculating sqrt is slow, so instead you can use the perfect squares. check every odd number between them and use the sqrt of the lower perfect square in each range as the greatest number you have to check (but only check prime numbers less than it).
Brody Brooks
0
Jose Cruz
Prime numbers have to be greater than 1
Jordan Turner
Both 6 and 25 are composite and not prime
Jack Thomas
Try isPrime(2).
Christopher Foster
>Python programmers
lmao
Jeremiah Anderson
>ridiculously hard
nigger I did this shit in highschool if someone cant do it after a BS in CS then they should unironically kill themselves for being a waste of carbon
Jacob Brooks
>Python PROGRAMMERS
Landon Adams
that's not the actual reasoning why 0 is not prime, retard
Jose Russell
Logan Sanders
nice catch my man
Hudson Ross
It's been beaten in my head the algorithm for finding prime numbers thanks to interview after interview. Slipping such an addition to fizzbuzz is nothing to me.
Adrian Bell
so is this the ultimate final best of the best way to check if the number is prime?
Lucas Miller
>be interviewer
>bring advent of code page up during interview
Jonathan Brooks
My greatest weakness is vocabulary/algorithm memorization. It's my own fault for always defaulting to taking the 1 second to Google it but still. Even for things as common as primes I might forget what a prime number is. I know it's a mathematical term that can be expressed as an algorithm, but making sure I remember the lexical name combined with the mathematical formula is where it falls apart. I'd rather not make assumptions and always confirm something is what I think it is by checking the reference first.
This is also due to heavy abstractions that come as a RESULT of practice. I don't remember how to floor an int because if I want to do that I just call floor() on it obviously. Implementing those functions are school exercises which means 10 years ago for me.
Xavier Rogers
learning programming by interview grinding has to be pretty legit.
Gavin Barnes
No. The fast algorithms use probabilistic methods first, like checking some values of Fermat's little theorem.
Julian Roberts
I actually quite sick of it actually. 200 apps out, I just want to work damnit.
Jaxson Rogers
>I don't remember how to floor an int
I think you are just retarded
Christopher Edwards
What's the point in remembering not only how to do it but how to implement it efficiently in several languages? It's totally irrelevant and counter to the whole point of abstraction in the first place imo. I don't want to think "I need to floor this, how do I do that, then what do I do" I want to think "I need to floor() this then something else"
Parker Martin
You don't seem to even understand what floor() is supposed to do.
Julian Williams
He's an ultrafinitist who believes 24 is the biggest number.
Connor Smith
>trial division
>not a primality test like miller rabin
>not at the very minimum pre-sieving up to sqrt(2**64-1), which is 4294967296, and the range has 203280221 primes, requiring 1.51GiB of storage to store at 8-bytes a number, allowing you to test trial division by primes only instead of all odd numbers
>probabilistic
They can be proven deterministic for below some numbers, actually:
>en.wikipedia.org
>if n < 18,446,744,073,709,551,616 = 2^64, it is enough to test a = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, and 37
So unless you're into bignum territory, primality testing is deterministic.
Jacob Walker
All I did was mistakenly say "an int" instead of "a number". Because internally, the "int" keyword and "number whos type is irrelevant" are synonymous. But you're missing the broader point by focusing on that detail.
Brody Hughes
BASED
Logan Cruz
>storing 8-byte prime numbers during a pre-sieve
>not setting bit indicators in a bit field
We'll get back to you about the job user.
Luke Edwards
Reading comprehension. He has experienced a situation where the interviewer fucked up, he never wrote what specific question it was.
Christopher Gomez
Is the joke that almost all prime numbers are uneven and following his orders of printing from 102 in decrements of 2 you'd never hit a prime number?
Isaac Nelson
user isn't missing anything. A number is a number, an int is an int. You may have misspoken when you said "floor an int" but that doesn't make it any more of a dumb thing to say.
Ethan Lee
I admitted it was a mistake and expressed it's not the focal point. What more do you want? What sense is there in being a pedant?
Blake Anderson
The only way to find prime numbers to use a prime sieve. I wasn't even taught this in 4th grade like everybody else, so when I was asked to calculate primes up to 100 and sort them, I couldn't. I wrote a shitty function that looked like
const isPrime = (num) => {
for (let i = 0; i < num; i++) {
if (num % i === 0) {
return false;
}
}
return true;
}
I hate myself for this... but more importantly, I hate that this random trivia question ruined my chances of getting in. Was I supposed to invent a prime sieve on the spot? if only I knew about it, if only it wasn't buried by meaningful topics like hash tables, trees, and other important data structures.
Excuse my JS. I've been using exclusively for the last 1.5 years and I've forgot how to Java.
Adrian Collins
There's nothing wrong with your solution. A prime sieve would use growing amounts of space to store all the primes. Your solution uses constant space at the cost of time. Note that the state of the art for prime testing is not something anyone can be reasonably expected to produce during an interview.
Brandon Robinson
>Note that the state of the art for prime testing is not something anyone can be reasonably expected to produce during an interview.
This is why you don't have a job
Julian Gray
>A prime sieve would use growing amounts of space to store all the primes.
Good lord, being this nocode.
Julian Morris
You're gonna come up with this on the spot?
en.wikipedia.org
Jackson Adams
>Was I supposed to invent a prime sieve on the spot?
I gave up on teaching myself programming because I was learning from a book that was full of challenges like that. I really struggled to do any of them, and thought, "If I'm this bad at the basic stuff, maybe I should just quit." But I always suspected I was missing something, because there's no way anyone could read that book and think it was easy.
Connor Ortiz
If you can't write in 5 minutes or less a function which checks if a single integer is prime or not, you don't deserve to call yourself even a hobbyist coder.
Hint: you don't need a fucking sieve to check if a certain number is prime.
Matthew Rodriguez
We only want the BEST for the job; if you aren't up to the likes of Dinesh and Shaquana, then why are you applying?
Henry Morris
The poster I responded to expected a state of the art solution
A basic prime testing function is a different matter entirely and I never claimed it's unreasonable to ask for one in an interview
Liam Howard
35 also works, turbo-brainlet. its prime factorization is 5x7
Lincoln Reyes
>The poster I responded to expected a state of the art solution
No, he didn't, autismo. He was merely disagreeing with your naive assumption that one was required.
Cooper Smith
>He was merely disagreeing with your naive assumption that one was required.
I didn't assume that retard. I was replying to
who gave a perfectly good solution but felt it wasn't good enough and I was informing him that he doesn't need a state of the art solution
Mason Gomez
>57
>not a prime
Jeremiah Moore
Same shit
Zachary Myers
#include
#include
static int *primes;
static int capacity;
static int size;
static int init(void)
{
primes = malloc(10 * sizeof(sizeof(primes[0])));
if (primes == NULL) {
return -1;
}
capacity = 10;
size = 0;
return 0;
}
static void finish(void)
{
free(primes);
}
static int add(int p)
{
printf("%d\n", p);
if (size == capacity) {
int *np;
capacity *= 2;
np = realloc(primes, capacity * sizeof(primes[0]));
if (np == NULL) {
return -1;
}
primes = np;
}
primes[size++] = p;
return 0;
}
static int isnew(int i)
{
int j;
for (j = 0; j < size; j++) {
if (i % primes[j] == 0) {
return 0;
}
}
return 1;
}
int main(int argc, char *argv[])
{
int i;
int l;
switch (argc) {
case 1:
l = 1000000;
break;
case 2:
if (sscanf(argv[1], "%d", &l) != 1) {
fprintf(stderr, "usage: %s [LIMIT]\n", argv[0]);
return EXIT_FAILURE;
}
break;
default:
fprintf(stderr, "usage: %s [LIMIT]\n", argv[0]);
return EXIT_FAILURE;
}
if (init() != 0) {
fprintf(stderr, "out of mem\n");
return EXIT_FAILURE;
}
for (i = 2; i
Joshua Russell
What the absolute fuck? what company is this? how do you get this retarded?
x mod 2 > 0 and x mod 3 > 0 does not mean x is a prime.
The definition of a prime number is a number that is only divisible by itself and 1.
Liam Bailey
constexpr int max = 103;
bool sieve_composite[max] = {0};
for(int i = 2; i < max; ++i){
if(!sieve_composite[i])
for(int j = i*i; j < max; j+=i)
sieve_composite[j]=1;
}
for(int i = max-1; i > 3; --i){
if(sieve_composite[i])
std::cout
Luke Sanchez
def isPrime(num):
if num < 2:
return False
else:
for i in range(num):
if num % i == 0:
return False
return True
How did I do?
Gavin Jackson
def is_prime(num):
while(1){
require(is-odd.js)
#include
void *prime = malloc(sizeof *stdlib.h);
if not !True: print(return;);
}
Jace Cox
sieve of eratosthenes is pretty cool and has a great historical importance. It's not the most efficient though.
Aiden Powell
>pointless else statement causing unnecessary indentation
>checking even numbers when 2 suffices
>not just checking if odd
>checking the entire range instead of just sqrt(n)
Failed middle school math tier.
William Nelson
He was trolling.
Ryan Young
If you don't care about complexity then finding prime numbers is easy.
Nathan Baker
Genius, when can you start?
Jackson Ramirez
Noone says it's necessarily easy. It also depends what book you read, some are more targeted towards universities or mathematicians learning to code.
Gavin Gomez
Doubt you finished high school with that level of reading.