POJ 2208 已知边四面体六个长度，计算体积

Description

Input

Output

Sample Input

1000 1000 1000 3 4 5

Sample Output

依据边来求出四面体的高，然后公式计算。

代码：

/* ***********************************************
Author :_rabbit
Created Time :2014/5/9 21:32:01
File Name :5.cpp
************************************************ */
#pragma comment(linker, "/STACK:102400000,102400000")
#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <sstream>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <string>
#include <time.h>
#include <math.h>
#include <queue>
#include <stack>
#include <set>
#include <map>
using namespace std;
#define INF 0x3f3f3f3f
#define eps 1e-8
#define pi acos(-1.0)
typedef long long ll;
double volume(double a,double b,double c,double d,double e,double f){
	double a2=a*a,b2=b*b,c2=c*c,d2=d*d,e2=e*e,f2=f*f;
	double tr1=acos((c2+b2-f2)/(2*b*c));
	double tr2=acos((a2+c2-e2)/(2*a*c));
	double tr3=acos((a2+b2-d2)/(2*a*b));
	double tr4=(tr1+tr2+tr3)/2;
	double temp=sqrt(sin(tr4)*sin(tr4-tr1)*sin(tr4-tr2)*sin(tr4-tr3));
	return a*b*c*temp/3;
}
int main()
{
     //freopen("data.in","r",stdin);
     //freopen("data.out","w",stdout);
     double a,b,c,d,e,f;
	 while(cin>>a>>b>>c>>d>>e>>f)printf("%.4f\n",volume(a,b,c,d,e,f));
     return 0;
}