Problem 7(10001st prime)

Problem 7(10001st prime)

By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.

What is the 10 001st prime number?

In Python:

# PE7 10001st prime
import time
import math

startTime = time.time()
order = 1
num = 1


def is_prime(n):
    if n == 1:
        return False
    elif n == 2:
        return True
    else:
        i = 2
        while i < math.ceil(math.sqrt(n)) + 1:
            if n % i == 0:
                return False
            else:
                i += 1
        return True


while order < 10001:
    num += 2
    if is_prime(num):
        order += 1
    else:
        continue

print(num)
print(time.time() - startTime, "seconds")

Run time: 1.2066988945007324 seconds

In Java:

//Euler7 10001st prime

package project_euler;

public class Euler7 {

public static boolean isPrime(int n) {

if (n == 1) {

return false;

}

else if (n == 2) {

return true;

}

else {

int i = 2;

while (i < Math.ceil(Math.sqrt(n))+1) {

if (n % i == 0) {

return false;

}

else {

i += 1;

}

}

return true;

}

}

public static void main(String[] args) {

long startTime = System.currentTimeMillis();

int num = 1;

int order = 1;

while (order < 10001) {

num += 2;

if (isPrime(num)) {

order += 1;

}

else {

continue;

}

}

System.out.println(num);

long endTime = System.currentTimeMillis();

System.out.println((double)(endTime - startTime) / (double)1000 + "seconds");

}

}

Run time: 0.048seconds

solution: 104743

[from Project Euler: https://projecteuler.net/problem=7]