#include using namespace std; typedef signed long long ll; #undef _P #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<(to);x++) #define FORR(x,arr) for(auto& x:arr) #define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) //------------------------------------------------------- double X[4],Y[4],Z[4]; double PX,PY,PZ; void solve() { int i,j,k,l,x,y; string s; FOR(i,4) cin>>X[i]>>Y[i]>>Z[i]; PX=Y[1]*Z[2]-Z[1]*Y[2]; PY=Z[1]*X[2]-X[1]*Z[2]; PZ=X[1]*Y[2]-Y[1]*X[2]; double r=sqrt(PX*PX+PY*PY+PZ*PZ); PX/=r; PY/=r; PZ/=r; double DX=X[3]-X[0]; double DY=Y[3]-Y[0]; double DZ=Z[3]-Z[0]; double d=PX*DX+PY*DY+PZ*DZ; X[3]-=d*PX; Y[3]-=d*PY; Z[3]-=d*PZ; int A[3]={}; FOR(i,3) { double ax=X[(i+1)%3]-X[i]; double ay=Y[(i+1)%3]-Y[i]; double az=Z[(i+1)%3]-Z[i]; double bx=X[3]-X[i]; double by=Y[3]-Y[i]; double bz=Z[3]-Z[i]; double cx=ay*bz-az*by; double cy=az*bx-ax*bz; double cz=ax*by-ay*bx; if(cx<0) A[i]++; if(cy<0) A[i]++; if(cz<0) A[i]++; } if(A[0]==A[1] && A[0]==A[2]) cout<<"YES"<