> //5 -1 -1 4 3 1 1 0 3 4 0
> #include<stdio.h>
> #include<math.h>
> #include<Limits.h>
> #define fun1(a,b) a>b?b:a
> #define fun2(a,b) a>b?a:b
> typedef struct
>  {
>   int x;
>   int y;
> }POINT;
> POINT point[50005],a[50005],pos1[10],pos2[10], *temp, source, small;
> int k;
> void Find(int n)
> {
>   int i, mult;
>   temp = &point[0];
>   for(i=1; i<n; i++)
>   {
>     if(point[i].y<temp->y||(point[i].y==temp->y&&point[i].x<temp->x))
>         temp=&point[i];
>   }
>   return;
> }
> int Mult(POINT a, POINT b)
> {
>   return (a.x*b.y - b.x*a.y);//比较斜率//叉积.
> }
> double Dis(POINT k)
> {
>   return sqrt((k.x)*(k.x)+(k.y)*(k.y));
> }
> int MultBigger(POINT a, POINT b, POINT c)
> {
>   POINT p, q;
>   p.x = b.x-a.x;
>   p.y = b.y-a.y;
>   q.x = c.x-b.x;
>   q.y = c.y-b.y;
>   if(Mult(p,q) < 0) return 1;/*叉积运算*///斜率最小原则
>   else if(Mult(p,q) > 0) return 0;
>   else
>   {
>     if(Dis(q)>Dis(p)) return 1;
>     else return 0;
>   }
> }
> int Search(int n)
> {
>   int i;
>   POINT temper;//source = *temp; small = *temp;
>   temper=source;
>   for(i=0; i<n; i++)
>   {
>     if(point[i].x ==INT_MAX)//已检查过的点 
>         continue;
>     if (MultBigger(source,temper,point[i]))
>     {
>         temp=&point[i];
>         temper=point[i];
>     }
>   }//for
>   if(MultBigger(source, temper, small)) return 1;//回到初始点 
>   a[k].x=temp->x;a[k].y=temp->y;k++;//回到初始点时source和temper相同.
>   source=*temp;
>   temp->x=INT_MAX;
>   return 0;
> }
> int main()
> {
>   int n, i, c,j,m,D,D1,D2,m0,n0;
>   double x1,y1,x2,y2,x3,y3,x4,y4;
>   double min,max;
>   while(scanf("%d%d",&n,&c)!=EOF)
>   {
>     for(i=0;i<n;i++)
>     scanf("%d",&point[i].x);
>     for(i=0;i<n;i++)
>     scanf("%d",&point[i].y);
>     if(n==1)
>     {
>      printf("%d.000 %d.000\n",point[0].y,point[0].y);
>      continue;
>     }
>     Find(n);         /*找出最下、最右点*/
>     source = *temp;
>     small = *temp;
>     //printf("%d %d\n",small.x,small.y);
>     k=0;
>     k++;
>     a[k].x=small.x;a[k].y=small.y;k++;
>     temp->x=INT_MAX;
>     //printf("%d\n",temp->x);
>     for(i=0;i<n;i++)
>     if(Search(n))break;/*按叉积搜索 break 时回到出发点*/
>     //printf("%d\n",k);
>     //for(i=1;i<k;i++)
>     //printf("%d %d\n",a[i].x,a[i].y);
>     a[k].x=a[1].x;a[k].y=a[1].y;
>     m0=n0=0;
>     for(i=1;i<k;i++)
>     {
>      if(c>=a[i].x&&c<=a[i+1].x||c>=a[i+1].x&&c<=a[i].x)
>      {m0++;n0++;
>       pos1[m0].x=a[i].x;pos1[m0].y=a[i].y;pos2[n0].x=a[i+1].x;
>       pos2[n0].y=a[i+1].y;
>      }
>     }
>     //for(i=1;i<=2;i++)
>     //printf("%d %d %d %d\n",pos1[i].x,pos1[i].y,pos2[i].x,pos2[i].y);
>     if((pos2[1].x-pos1[1].x)!=0)
>     min=(pos2[1].y-pos1[1].y)*(c-pos1[1].x)/(pos2[1].x-pos1[1].x)+pos1[1].y;
>     else min=fun1(pos1[1].y,pos2[1].y);
>     if((pos2[2].x-pos1[2].x)!=0)
>     max=(pos2[2].y-pos1[2].y)*(c-pos1[2].x)/(pos2[2].x-pos1[2].x)+pos1[2].y;
>     else max=fun2(pos2[1].y,pos2[2].y);
>     printf("%.3lf %.3lf\n",min,max);
>     }
> }//main
> /*
> 3 1
> 0 2 1
> 0 0 1
> 5 2
> -1 4 1 0 4
> -1 3 1 3 0
> */
>