[Euler]Problem 30 - Digit fifth powers

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

1634 = 1 4 + 6 4 + 3 4 + 4 4
8208 = 8 4 + 2 4 + 0 4 + 8 4
9474 = 9 4 + 4 4 + 7 4 + 4 4

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.


import java.util.HashMap;
import java.util.Map;

public class DigitFifthPowers {
	Map<Integer, Double> map = new HashMap<Integer, Double>();

	public static void main(String[] args) {
		long before = System.currentTimeMillis();

		new DigitFifthPowers().calculate();

		System.out.println("elapsed time is : " + (System.currentTimeMillis() - before));
	}

	private void calculate() {
		int count = 0;

		for (int i = 0; i < 10; i++) {
			map.put(i, Math.pow(i, 5));
		}

		System.out.print("the numbers that can be written as the sum of fifth powers of their digits is : ");

		for (int i = 2; i < 1000000; i++) {
			if (isThisIt(i)) {
				System.out.print(i + " ");
				count += i;
			}
		}

		System.out.println();
		System.out.println(count);
	}

	private boolean isThisIt(int i) {
		Double sumOfDigits = 0d;
		int temp = i;

		while (temp > 0) {
			sumOfDigits += map.get(temp % 10);
			temp /= 10;
		}

		return sumOfDigits == i;
	}

}


console:

the numbers that can be written as the sum of fifth powers of their digits is : 4150 4151 54748 92727 93084 194979 
443839
elapsed time is : 111

评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值