Rectangle and Square（判断正方形、矩形）

http://acm.sdut.edu.cn:8080/vjudge/contest/view.action?cid=42#problem/D

改了N多次之后终于A了，一直在改判断正方形和矩形那，判断正方形时算出六条边再排序，若前四条边相等并且与后两条边满足勾股定理，说明是正方形，

判断矩形时，我先对结构体二级排序，这样四个点有确定的顺序，再用点积判断是否有三个角是直角，是的话就是矩形。

 #include<stdio.h>
 #include<string.h>
 #include<algorithm>
 using namespace std;

 struct node
 {
     int x,y;
 }point[];

 int cmp(const struct node a,const struct node b)
 {
     if(a.x == b.x)
         return a.y < b.y;
     return a.x < b.x;
 }
 int dot(const struct node a, const struct node b,const struct node c, const struct node d)
 {
     int ans = (a.x-b.x)*(c.x-d.x) + (a.y-b.y)*(c.y-d.y);
     if(ans == ) return ;
     return ;
 }

 int dis(const struct node a, const struct node b)
 {
      return (a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y);
 }

 int main()
 {
     while(~scanf("%d %d",&point[].x,&point[].y))
     {
         bool vis[] = {false};
         for(int i = ; i <= ; i++)
             scanf("%d %d",&point[i].x,&point[i].y);
         int flag = ;
         int cnt;
         struct node t_point[];
         for(int i = ; i <= ; i++)
         {
             for(int j = i+; j <= ; j++)
             {
                 for(int k = j+; k <= ; k++)
                 {
                     for(int l = k+; l <= ; l++)
                     {
                         int distance[];
                         distance[] = dis(point[i],point[j]);
                         distance[] = dis(point[i],point[k]);
                         distance[] = dis(point[i],point[l]);
                         distance[] = dis(point[j],point[k]);
                         distance[] = dis(point[j],point[l]);
                         distance[] = dis(point[k],point[l]);
                         sort(distance,distance+);
                         if( distance[] == distance[] &&
                             distance[] == distance[] &&
                             distance[] == distance[] &&
                             distance[] == distance[] &&
                             (distance[] + distance[] == distance[]))
                             {
                                 flag = ;
                                 vis[i] = true;
                                 vis[j] = true;
                                 vis[k] = true;
                                 vis[l] = true;
                                 break;
                             }
                     }
                     if(flag) break;
                 }
                 if(flag) break;
             }
             if(flag) break;
         }
         if(!flag)
             printf("NO\n");

         else
         {
             int tmp1[],tmp2[],t1 = ,t2 = ;
             cnt = ;
             for(int i = ; i <= ; i++)
             {
                 if(!vis[i])
                 {
                     t_point[cnt++] = point[i];
                     tmp2[t2++] = i;
                 }
                 else tmp1[t1++] = i;
             }
             sort(t_point,t_point+cnt,cmp);

             if(dot(t_point[],t_point[],t_point[],t_point[]) &&
                dot(t_point[],t_point[],t_point[],t_point[]) &&
                dot(t_point[],t_point[],t_point[],t_point[]))
                {
                    printf("YES\n");
                    for(int i = ; i < t1-; i++)
                         printf("%d ",tmp1[i]);
                     printf("%d\n",tmp1[t1-]);
                    for(int i = ; i < t2-; i++)
                         printf("%d ",tmp2[i]);
                     printf("%d\n",tmp2[t2-]);
                }
             else printf("NO\n");

         }

     }
     return ;
 }