NYOJ 773 开方数

#include <stdio.h>
#include <math.h>
int n;
double p;

int cal(double a)//计算加判断 
{
    double cmpnum = 1;
    for(int i=1;i<=n;i++)
    {
        cmpnum *= a;
    }
    if(cmpnum >=p)
        return 1;
    else
        return 0;
}

int main()
{
    double r;
    double l;
    double mid;
    //二分思想 
    while(scanf("%d %lf",&n,&p)&&n)
    {
        l = 0;
        r = 1000000000;
        mid = (l+r)/2;
        
        while(l+0.1<r)
        {
            if(cal(mid)==1)
            {
                r = mid;
            }
            else
            {
                l = mid;
            }
            mid = (r+l)/2;
        }
        printf("%.0lf\n",l);
    }
        
    
    
    return 0;
}