You have exactly 30 seconds to find the sum of all primes

import primes

muh_primes = primes.primes
sum = 0

for i < 2000000:
    if i in muh_primes:
        sum += i

print(sum)

>>61541722
I just like to shorten things.

require 'prime'
m=2
(3...200000).step(2){|n|m+=n if Prime.prime?(n)}
puts m

Easy, I'll just go to Project Euler and find the answer from when I did this the first time years ago.

Why are you adding everything to an array beforehand? You're only using the value once, so just add it to a running sum.

>>61542876

for i < 2000000:

mixing up your for and while loops there senpai

File: g.png (12KB, 722x384px) Image search: [Google]

12KB, 722x384px

did i do right /g/?
can anyone confirm this?

>>61545527
Very nice

>>61545527
This is excellent. paste dat der script anon.

Took a bit longer that 30 seconds

+/{(⍳⍵)×{2=+/0=x|⍨⍳x←⍵}¨⍵}2000000

>>61543218

require 'prime'

Prime.each(2000000).reduce(:+)

1.999.999 * 2.000.000 / 2 = 1.999.999.000.000

How to be better than /g/ without a computer.

>>61541722

(defvar *sieve* nil)

(defun sieve-of-eratosthenes (limit)
  (let ((nums (make-array limit :initial-element nil)))
    (loop for p from 2 below limit
       do (loop for multiple from (+ p p) by p below limit
             do (setf (aref nums multiple) t))
       finally (return nums))))

(defmacro with-prime-sieve (below limit &rest body)
  (declare (ignore below))
  `(let ((*sieve* (sieve-of-eratosthenes ,limit)))
     (progn ,@body)))

(defun primep (y)
  (let ((sieve (or *sieve* (sieve-of-eratosthenes (1+ y)))))
    (not (aref sieve y))))

(with-prime-sieve below 2000000
  (loop for x from 2 below 2000000
     when (primep x)
     summing x))

Took ~0.08 seconds.

What do I win?

>>61541722
You would have to do a terrible job to write a program that takes more than 30 seconds to do that.

>yfw the language that everyone shits on is the fastest ITT

:code:

System.out.println("#Hillary2016. I'm with her.");

:code:

>>61545527
I thought I told you to never show your face here ever again. What the fuck is wrong with you asshole! 149K LOC?

File: 1492590161135.png (4KB, 264x117px) Image search: [Google]

4KB, 264x117px

>>61545527
optimization pass

>>61547389
fuck you I do what I want
filedropper com / primes

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define FALSE 0
#define TRUE !FALSE

void make_sieve(long limit, char **sieve_arr) {
  if (*sieve_arr == NULL) {
    *sieve_arr = malloc(limit);
  }
  memset(*sieve_arr, FALSE, limit);

  for (long i = 2; i < limit + 1; i++)
    for (long multiple = i + i; multiple < limit + 1; multiple += i)
      (*sieve_arr)[multiple] = TRUE;
}

int main() {
  char *sieve_arr = NULL;
  make_sieve(2000000, &sieve_arr);

  long sum = 0;
  for (long i = 2; i <= 2000000; i++)
    if (!sieve_arr[i])
      sum += i;

  free(sieve_arr);
  printf("sum: %ld\n", sum);
}

0.11

File: holy shit.jpg (23KB, 480x674px) Image search: [Google]

23KB, 480x674px

>>61547461
holy shit

>>61541722

primes() {
    int i;
    unsigned long long int sum = 1 + 2;
    /* evens except 2 can't be a prime */
    for (i = 3; i < 2000000; i+=2) {
        if (isPrime(i)) s+= i;
    }
    return s;
}

isPrime(int n) {
    if (n & 1 == 0) return 0;
    for (i = 3; i <= sqrt(n); i+=2) {
        if (n % i == 0) return 0
    }
    return 1;
}

>>61547473
>>61547485
That's how you do it asshole. NOT fucking 148K LOC. We're you dropped on your fucking head?

>>61548306
yeah but which one is easier to understand

readability > everything else

Kotlin:

fun main(args: Array<String>) {
    var sum: Long = 0
    (1..2000000).filter { isPrime(it) }.forEach { sum += it }
    println("The total is: $sum")
}

fun isPrime(number: Int): Boolean {
    if (number <= 1) return false
    return isPrimeRecursive(number, number - 1)
}

tailrec fun isPrimeRecursive(number: Int, divisor: Int): Boolean {
    if (divisor == 1) return true
    if (number % divisor == 0) return false
    else return isPrimeRecursive(number, divisor - 1)
}

>>61545527
I'm surprised that your editor didn't shit itself.

>>61548432
Right?

>>61548636
>his editor can't handle 150k LOC
re-evaluate your choices