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;
 }
}