> #include<stdio.h>
> #include<stdlib.h>
> #include<string.h>
> 
> struct In 
> { 
> int x; 
> int y; 
> }s[50001]; 
> 
> int flag[50001],num[50001],t;
> int search(int n)
> {
>     int max,sum,i,temp;
>     max=0;
>     sum=0;
>     for(i=0;i<t;i++)
>     {
>         if(s[i].x==n) 
>         {
>             temp=search(s[i].y);
>             if(temp>max) max=temp;       
>             sum+=temp;
>         }
>         if(s[i].x>n) break;       
>     }
>     flag[n]=max;
>     num[n]=sum;
>     return sum+1;
> }
> 
> int cmp( const void *a , const void *b) 
> { 
> struct In *c = (In *)a; 
> struct In *d = (In *)b; 
> if(c->x != d->x) return c->x - d->x; 
> else return c->y - d->y; 
> } 
> 
> int main()
> {
>     int i,j,pp,min;
>     
>     while(scanf("%d",&t)!=EOF)
>     {
>         s[0].x=0;
>         s[0].y=1;
>         for(i=1;i<t;i++)
>         scanf("%d%d",&s[i].x,&s[i].y);
>         qsort(s,t,sizeof(s[0]),cmp);
>         memset(flag,0,sizeof(flag));
>         search(0);
>         
>         for(i=1;i<=t;i++)
>         if(flag[i]<(t-1-num[i])) flag[i]=(t-1-num[i]);
>         
>         min=flag[1];
>         for(i=2;i<=t;i++)
>         {
>             if(min>flag[i]) min=flag[i];    
>         } 
>         
>         pp=0;
>         for(i=1;i<=t;i++)
>         {
>             if(min==flag[i]) 
>             {
>                 if(pp==0) 
>                 {
>                     printf("%d",i);
>                     pp=1;    
>                 }
>                 else printf(" %d",i);
>             }    
>         }
>         printf("\n");
>     }
>     return 0;    
> }
> 
其实我很好奇, 为什么这个程序不TLE呢