UVa-10341-Solve It

AOAPC I: Beginning Algorithm Contests (Rujia Liu) :: Volume 4. Algorithm Design

// 10341 - Solve It
#include <cstdio>
#include <cmath>
#define EPS 1e-7						// 精度要求苛刻...
int p, q, r, s, t, u;

double formula(double x)				// 单调递减
{
	return p*exp(-x) + q*sin(x) + r*cos(x) + s*tan(x) + t*x*x + u;
}

int main(void)
{
	while(scanf("%d%d%d%d%d%d",&p,&q,&r,&s,&t,&u) != EOF)
	{
		double a = 0, b = 1, m;
		if(formula(0)*formula(1) > 0)	// 边界分析
			printf("No solution\n");
		else
		{
			while(b - a > EPS)
			{
				m = (a + b) / 2;
				if(formula(a)*formula(m) > 0)
					a = m;
				else
					b = m;
			}
			printf("%.4f\n", m);
		}
	}
    return 0;
}