What is the sum of the digits of the number 2^1000?
//the sum of digits for b^p, in this problem b=2,p=1000
//https://projecteuler.net/problem=16
#include<bits/stdc++.h>
using namespace std;
#define LL long long
int digit[4000];
int main()
{
int i,j,k,n,m,d,b,p;
while(cin>>b>>p)
{
n=(int)(p*ceil(log(b))); //number of digit in b^p
memset(digit,0,sizeof(digit));
digit[0]=1;
for(i=0;i<p;i++)
{
int carry=0;
for(j=0;j<n;j++)
{
int num=digit[j]*b+carry;
digit[j]=num%10;
carry=num/10;
}
}
int sum=0;
for(i=0;i<n;i++)
sum=sum+digit[i];
cout<<sum<<endl;
}
return 0;
}
Advertisements
ACM Competitive Programmer
Leave a Reply