#include <stdio.h>
 
//this gives you the power in a time of O(log N)
 
//for numbers that may go out of range of int...use "long long int" in place of "int"
 
//for understanding the program logic even better you can visit...http://w...content-available-to-author-only...c.com/fast-exponentiation-algorithms/
 
int exp_by_squaring(int n,int pow)//this is a recursive solution...an iterative solution is also possible...!!!
{
    if(pow==0)//power is zero
        return 1;
    if(pow==1)//power is 1
        return n;
    if(pow&1)//pow is odd
    {
        int ans=exp_by_squaring(n,pow/2);
        return ans*ans*n;
    }
    //pow is even
    int ans=exp_by_squaring(n,pow/2);
    return ans*ans;
}
int main(void)
{
    printf("%d",exp_by_squaring(2,10));
	return 0;
}

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