【CodeForces - 215B】【Olympic Medal】(数学公式推导)

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题目:

The World Programming Olympics Medal is a metal disk, consisting of two parts: the first part is a ring with outer radius of r1 cm, inner radius of r2 cm, (0 < r2 < r1)made of metal with density p1 g/cm3. The second part is an inner disk with radius r2cm, it is made of metal with density p2 g/cm3. The disk is nested inside the ring.

The Olympic jury decided that r1 will take one of possible values of x1, x2, ..., xn. It is up to jury to decide which particular value r1 will take. Similarly, the Olympic jury decided that p1 will take one of possible value of y1, y2, ..., ym, and p2 will take a value from list z1, z2, ..., zk.

According to most ancient traditions the ratio between the outer ring mass mout and the inner disk mass min must equal , where A, B are constants taken from ancient books. Now, to start making medals, the jury needs to take values for r1, p1, p2 and calculate the suitable value of r2.

The jury wants to choose the value that would maximize radius r2. Help the jury find the sought value of r2. Value r2 doesn't have to be an integer.

Medal has a uniform thickness throughout the area, the thickness of the inner disk is the same as the thickness of the outer ring.

Input

The first input line contains an integer n and a sequence of integers x1, x2, ..., xn. The second input line contains an integer m and a sequence of integers y1, y2, ..., ym. The third input line contains an integer k and a sequence of integers z1, z2, ..., zk. The last line contains two integers A and B.

All numbers given in the input are positive and do not exceed 5000. Each of the three sequences contains distinct numbers. The numbers in the lines are separated by spaces.

Output

Print a single real number — the sought value r2 with absolute or relative error of at most 10 - 6. It is guaranteed that the solution that meets the problem requirements exists.

Examples

Input

3 1 2 3
1 2
3 3 2 1
1 2

Output

2.683281573000

Input

4 2 3 6 4
2 1 2
3 10 6 8
2 1

Output

2.267786838055

Note

In the first sample the jury should choose the following values: r1 = 3, p1 = 2, p2 = 1.

解题报告:就是 (r1^2-r2^2)*p1/(r2^2)*p2=A/B  经过变换可以得到公式 r2^2=(B*p1*r1*r1)/(p1*B+p2*A); 找r2的最大值 就要找p1,r1最大值,p2最小值。最后得到最终结果 然后输出小数点后12位的输出就可以啦。

ac代码:

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<queue>
#include<cmath>
using namespace std;
typedef long long ll;
const int inf=99999999;
const int maxn=5e3+100;
int n;
double x[maxn],y[maxn],z[maxn];
#define PI 3.1415926
int main()
{
	double r1,r2,p1,p2,a,b;
	while(scanf("%d",&n)!=EOF)
	{
		r1=0;
		for(int i=0;i<n;i++)
		{
			scanf("%lf",&a);
			if(a>r1)
				r1=a;
		}
		scanf("%d",&n);
		p1=0;
		for(int i=0;i<n;i++)
		{
			scanf("%lf",&a);
			if(a>p1)
				p1=a;
		}
		scanf("%d",&n);
		p2=inf;
		for(int i=0;i<n;i++)
		{
			scanf("%lf",&a);
			if(a<p2)
				p2=a;
		}
		scanf("%lf%lf",&a,&b);
		printf("%.12lf\n",sqrt(b*r1*r1*p1/(a*p2+b*p1)));
		}

}

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转载自blog.csdn.net/qq_42505741/article/details/83549222