判斷四點共面

四個點構造三個向量，形成一個行列式
若行列式的值爲0，則共面；不爲0，則不共面

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
using namespace std;

struct Point
{
    int x,y,z;
} p[5];

int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        for(int i=0; i<4; i++)
            scanf("%d %d %d",&p[i].x,&p[i].y,&p[i].z);
        Point s1,s2,s3;
        s1.x=p[1].x-p[0].x;
        s1.y=p[1].y-p[0].y;
        s1.z=p[1].z-p[0].z;
        s2.x=p[2].x-p[0].x;
        s2.y=p[2].y-p[0].y;
        s2.z=p[2].z-p[0].z;
        s3.x=p[3].x-p[0].x;
        s3.y=p[3].y-p[0].y;
        s3.z=p[3].z-p[0].z;
        int ans;
        ans=s1.x*s2.y*s3.z+s1.y*s2.z*s3.x+s1.z*s2.x*s3.y-s1.z*s2.y*s3.x-s1.x*s2.z*s3.y-s1.y*s2.x*s3.z;
        if(ans==0)
            puts("Yes");
        else
            puts("No");
    }
}