学步园

http://acm.hdu.edu.cn/showproblem.php?pid=2289

题目大意：这道题就是给你一个圆台，里面装了一些水，现在告诉你圆台上下底半径，高度，水的体积，问你水的高度是多少。

解题思路：数学题，用到圆台求体积公式，照套就是，二分法逼近求值。

#include <stdio.h><br /> #include <math.h><br /> const double PI = acos(-1.0);<br /> const double eps = 0.000000001;</p> <p>double GetVolume(double r,double R,double h,double H)<br /> {<br /> double u = h/H*(R-r) + r;/*中部小圆台上底半径,根据比例可以求*/<br /> return PI/3*(r*r+r*u+u*u)*h;/*圆台面积公式*/<br /> }</p> <p>double BiSearch(double r,double R,double H,double v)<br /> {<br /> double left,right,tem,mid;<br /> left = 0,right = 100;<br /> while ((right-left)>eps)<br /> {<br /> mid = (left+right)/2;<br /> tem = GetVolume(r,R,mid,H);<br /> if (fabs(tem-v)<=eps)<br /> return mid;<br /> else if(tem<v)<br /> left=mid+eps;<br /> else<br /> right = mid-eps;<br /> }<br /> return (right+left)/2;<br /> }</p> <p>int main()<br /> {<br /> int test;<br /> double r,R,H,v;<br /> //freopen("e://1.txt","r",stdin);<br /> scanf("%d",&test);<br /> while (test--)<br /> {<br /> scanf("%lf%lf%lf%lf",&r,&R,&H,&v);<br /> printf("%.6lf/n",BiSearch(r,R,H,v));<br /> }<br /> return 0;<br /> }