UVA 10341 Solve It 二分

题目大意：给6个系数，问是否存在X使得等式成立

思路：二分。。。。

#include <stdio.h>
#include <math.h>
#define EEE 2.71828182845953581496
int p, q, r, s, t, u;
double v(double x)
{
    return (p*pow(EEE,-x)+q*sin(x)+r*cos(x)+s*tan(x)+t*x*x);
}
double f(double x,double z, double y)
{
double mid;
    while((y-z)>1e-10)
    {
        mid=(z+y)/2;
        if(v(mid)>x)
            z=mid+1e-10;
        else
            y=mid-1e-10;
    }
    return mid;
}
int main()
{
   while(~scanf("%d%d%d%d%d%d", &p, &q, &r, &s, &t, &u))
   {
       if(v(0)<-u||v(1)>-u)
       printf("No solution\n");
       else
       printf("%.4lf\n", f(-u,0,1));
   }
return 0;
}