HDU 2009 - 求数列的和

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2009

#include <math.h>
#include <stdio.h>

int main(void)
{
    int n;
    double x, s;

    while (scanf("%lf%d", &x, &n) != EOF)
    {
        for(s = 0.0; n--; x = sqrt(x))
            s += x;
        printf("%.2lf\n", s);
    }

    return 0;
}