## Problem:

We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once. For example, 2143 is a 4-digit pandigital and is also prime.

What is the largest n-digit pandigital prime that exists?

7652413

Code:

## The solution may include methods that will be found here: Library.java .

public interface EulerSolution{

public String run();

}
/*
* Solution to Project Euler problem 41
* By Nayuki Minase
*
* http://nayuki.eigenstate.org/page/project-euler-solutions
* https://github.com/nayuki/Project-Euler-solutions
*/

public final class p041 implements EulerSolution {

public static void main(String[] args) {
System.out.println(new p041().run());
}

public String run() {
for (int n = 9; n >= 1; n--) {
int[] digits = new int[n];
for (int i = 0; i < digits.length; i++)
digits[i] = i + 1;

int result = -1;
do {
if (Library.isPrime(toInteger(digits)))
result = toInteger(digits);
} while (Library.nextPermutation(digits));
if (result != -1)
return Integer.toString(result);
}
}

private static int toInteger(int[] digits) {
int result = 0;
for (int x : digits)
result = result * 10 + x;
return result;
}

}