Read the problem statement here:
Project Euler: https://projecteuler.net/problem=16
HackerRank: https://www.hackerrank.com/contests/projecteuler/challenges/euler016/problem
Java code:
import java.util.*; import java.math.*; class Solution{ public static void main(String[] args){ Scanner in = new Scanner(System.in); int t = in.nextInt(); while(t– > 0){ int n = in.nextInt(); BigInteger x = new BigInteger(“2”); //we need to raise 2 to the power of n x = x.pow(n); //result of pow() can be large long result = SumDigits(x); System.out.println(result); } in.close(); } static long SumDigits(BigInteger x){ long sum = 0; char[] Digits = x.toString().toCharArray(); for(char d:Digits){ //convert characters in char array to digit using //radix. Use 10 for decimal //radix means base of a system of numeration sum = sum + Character.digit(d, 10); } return sum; } }