View Code of Problem 67

#include <stdio.h>
 #include <string.h>
 int main()
  {
      int x1,y1,x2,y2,x3,y3,x4,y4;
      while (scanf("%d%d%d%d",&x1,&y1,&x2,&y2)!=EOF)
      {
          scanf("%d%d%d%d",&x3,&y3,&x4,&y4);
  
         int d1=(y2-y1)*(x4-x3);//判断两条直线斜率是否相等，和斜率不存在时判断两直线是否平行
         int d2=(x2-x1)*(y4-y3);
         
         int d3=(y3-y1)*(x2-x1);//判断两条直线是否重合
         int d4=(x3-x1)*(y2-y1);
         if (d1 == d2&&d3 !=d4)
             printf("No\n");
         else printf("Yes\n");
     }
     return 0;
 }