Java/ProjectEuler/Problem07.java at master · oribach/Java · GitHub

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package ProjectEuler;

/**

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

* 13.

* <p>What is the 10 001st prime number?

* <p>link: https://projecteuler.net/problem=7

public class Problem07 {

public static void main(String[] args) {

int[][] testNumbers = {

{1, 2},

{2, 3},

{3, 5},

{4, 7},

{5, 11},

{6, 13},

{20, 71},

{50, 229},

{100, 541}

};

for (int[] number : testNumbers) {

assert solution1(number[0]) == number[1];

}

/***

* Checks if a number is prime or not

* @param number the number

* @return {@code true} if {@code number} is prime

private static boolean isPrime(int number) {

if (number == 2) {

return true;

}

if (number < 2 || number % 2 == 0) {

return false;

}

for (int i = 3, limit = (int) Math.sqrt(number); i <= limit; i += 2) {

if (number % i == 0) {

return false;

}

return true;

}

private static int solution1(int n) {

int count = 0;

int number = 1;

while (count != n) {

if (isPrime(++number)) {

count++;

}

return number;

}

Java/ProjectEuler/Problem07.java at master · oribach/Java · GitHub

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