NYOJ68三点顺序

#include <cstdio>
#include <cmath>

int main()

{
int x1,y1,x2,y2,x3,y3;
while(~scanf("%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3),x1+y1+x2+y2+x3+y3)
{
int tx = x3 - x1;   //向量AC
int ty = y3 - y1;
int tx1 = x2 - x1;   //向量AB
int ty1 = y2 - y1;
if(tx * ty1 - tx1 * ty > 0) // 叉积大于0表示顺时针
printf("1\n");
else
printf("0\n");
}
return 0;
}