problem16 (Power digit sum)

problem16 (Power digit sum)

215 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
What is the sum of the digits of the number 21000?

In Python:

# Power digit sum
import time

startTime = time.time()

strNum = str(pow(2,1000))
numList = [int(num) for num in strNum]
print(sum(numList))

endTime = time.time()
print(endTime - startTime, "seconds")

Run time: 0.0006120204925537109 seconds


In Java:

//Euler16 Power digit sum

package project_euler;


import java.math.BigInteger;


public class Euler16 {
	public static void main(String[] args) {
		long startTime = System.currentTimeMillis();
		double sum = 0;
		BigInteger num = BigInteger.valueOf(2).pow(1000);
		String numString = num.toString();
		for (int i = 0; i < numString.length(); i++) {
			sum += Integer.parseInt(numString.charAt(i) + "");
		}
		System.out.println(sum);
		long endTime = System.currentTimeMillis();
		System.out.println((double)(endTime - startTime)/(double)1000 + "seconds");
	}
}

Run time: 0.006seconds


solution: 1366

[from Project Euler: https://projecteuler.net/problem=16]