project euler 30

Problem 30

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Digit fifth powers

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.

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各位数字的五次幂

令人惊讶的是，只有三个数可以写成它们各位数字的四次幂之和：

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

由于1 = 14不是一个和，所以这里并没有把它包括进去。

这些数的和是1634 + 8208 + 9474 = 19316。

找出所有可以写成它们各位数字的五次幂之和的数，并求这些数的和。

package projecteuler;import java.util.ArrayList;import java.util.List;import org.junit.Test;public class Prj30 {/** * 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. */@Testpublic void test() {int sum = 0;for (int i = 10; i < Math.pow(10, 6); i++) {if (checkCondition(i)) {System.out.println(i);sum += i;}}System.out.println("sum=" + sum);}private boolean checkCondition(int val) {List<Integer> data = new ArrayList<Integer>();int num = val;while( num >= 10){data.add(num % 10);num /= 10;}data.add(num);int sum = 0;for( int i = 0 ; i < data.size(); i ++){sum += Math.pow(data.get(i), 5);}return sum == val;}public static class CalculateParams{/** * 横向网格点数 */public int m;/** * 纵向网格个数 */public int n;/** * 网格间距 */public int netSize;/** * 网格点数值 */public double[] val;/** * 等直面数值数组 */public double[] contourVal;/** * 等直面个数 */public int coutourNum;}}