Project Euler > Problem 30 > Digit fifth powers (Java Solution)

Problem:

Surprisingly there are only three numbers that can be written as the sum of fourth powers of their digits:

1634 = 14 + 64 + 34 + 44
8208 = 84 + 24 + 04 + 84
9474 = 94 + 44 + 74 + 44

As 1 = 14 is not a sum it is not included.

The sum of these numbers is 1634 + 8208 + 9474 = 19316.

Find the sum of all the numbers that can be written as the sum of fifth powers of their digits.

Solution:

443839

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

public interface EulerSolution{

public String run();

}

/* 
 * Solution to Project Euler problem 30
 * By Nayuki Minase
 * 
 * http://nayuki.eigenstate.org/page/project-euler-solutions
 * https://github.com/nayuki/Project-Euler-solutions
 */


public final class p030 implements EulerSolution {
 
 public static void main(String[] args) {
  System.out.println(new p030().run());
 }
 
 
 public String run() {
  // As stated in the problem, 1 = 1^5 is excluded.
  // If a number has at least n >= 7 digits, then even if every digit is 9,
  // n * 9^5 is still less than the number (which is at least 10^n).
  int sum = 0;
  for (int i = 2; i < 1000000; i++) {
   if (i == fifthPowerDigitSum(i))
    sum += i;
  }
  return Integer.toString(sum);
 }
 
 
 private static int fifthPowerDigitSum(int x) {
  int sum = 0;
  while (x != 0) {
   int y = x % 10;
   sum += y * y * y * y * y;
   x /= 10;
  }
  return sum;
 }
 
}