project euler 34

Problem 34

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Digit factorials

145 is a curious number, as 1! + 4! + 5! = 1 + 24 + 120 = 145.

Find the sum of all numbers which are equal to the sum of the factorial of their digits.

Note: as 1! = 1 and 2! = 2 are not sums they are not included.

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各位数字的阶乘

145是个有趣的数，因为1! + 4! + 5! = 1 + 24 + 120 = 145。

找出所有各位数字的阶乘和等于其本身的数，并求它们的和。

注意：因为1! = 1和2! = 2不是和的形式，所以它们并不在讨论范围内。

package projecteuler;import java.util.HashSet;import java.util.Set;import org.junit.Test;public class Prj34 {/** * 145 is a curious number, as 1! + 4! + 5! = 1 + 24 + 120 = 145.Find the sum of all numbers which are equal to the sum of the factorial of their digits.Note: as 1! = 1 and 2! = 2 are not sums they are not included. */@Testpublic void test(){System.out.println(Calculator.calculate());}public static class Calculator{public static long calculate(){long val = (long) Math.pow(10, getBits() - 1);Set<Long> set = new HashSet<Long>();for( long i = 3 ; i < val ; i ++){if( checkNum(i)){set.add(i);System.out.println(i);}if( i % 10000 == 0){System.out.println("iter ="  + i);}}long sum = 0;for( long val_ : set){sum += val_ ;System.out.println(val_);}System.out.println(sum);return sum;}private static int getBits(){int val = NN.NINE.getVal();int bits = 1;while( val * bits >= Math.pow(10,  bits - 1)){bits += 1;}return bits;}private static boolean checkNum(long i) {int sum = 0;int num = 0;long val = i;while( val >= 10){num = Long.valueOf( val % 10).intValue();sum += NN.getNN(num ).getVal();val /= 10;}num = Long.valueOf( val).intValue();sum += NN.getNN(num).getVal();if( sum == i){return true;}else {return false;}}}public static enum NN{ZERO(0),ONE(1),TWO(2 * 1),THREE(3 * 2 * 1),FOUR(4 * 3 * 2 * 1),FIVE(5 * 4 * 3 * 2 * 1),SIX(6 * 5 * 4 * 3 * 2 * 1),SEVEN(7 * 6 * 5 * 4 * 3 * 2 * 1),EIGHT(8 * 7 * 6 * 5 * 4 * 3 * 2 * 1),NINE(9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1);private int val;private NN(int val){if( val == 0){this.val = 1;return;}this.val = val;}public int getVal(){return this.val;}public static NN getNN(int val){switch (val) {case 0: return ZERO;case 1: return ONE;case 2: return TWO;case 3: return THREE;case 4: return FOUR;case 5: return FIVE;case 6: return SIX;case 7: return SEVEN;case 8: return EIGHT;case 9: return NINE;default:return ZERO;}}}}