欧拉公式求四面体的体积

欧拉公式的推理和最终表达式：​​https://dayi.jd100.com/question/2051787/​​

欧拉公式应用：题目：​​https://cn.vjudge.net/contest/242365#problem/H​​​

ac代码：

#include<iostream>
#include<queue>
# include<bits/stdc++.h>
using namespace std;
int main(){
double p,q, r, n, m,  l;
while(cin>>n>>m>>p>>l>>q>>r){
    double rr = r * r, mm = m * m, nn = n * n;
    double pp = p * p, qq = q * q, ll = l * l;
    double x1 = (pp + qq - nn) / 2.0, x2 = (pp + rr - mm) / 2.0, x3 = (qq + rr - ll) / 2.0;
    double v = pp * (qq * rr - x3 * x3) - x1 * (x1  * rr - x2 * x3) + x2 * (x1 * x3 - qq * x2);
    cout<<fixed<<setprecision(4)<<sqrt(v) / 6.0<<endl;
}
    return 0;
}