营业额统计

[HNOI2002]营业额统计 一个丰富的OI题库 http://www.zybbs.org/JudgeOnline/ 这题其实很一道很裸的Splay_tree,每次插入一个节点，我们就把它旋转到根节点,然后把最靠近这个节点的两个值(左子树的最大值,右子树的最小值)找出来比较一下就行了，对于Splay_tree  我就不累叙了；

#include<iostream>
#include<cstdio>
#include<string>
#include<cstdlib>
using namespace std;
class Tree
{
 public:
   int num;
   int cnt;
   Tree  *lchild,*rchild,*father;
   Tree( int n = 0 ){ num = n; lchild = rchild = father =NULL; cnt= 0;}    
};
class Splay
{
private:
       Tree *root;
       int count;
public:
     Splay( ){ root =  NULL ; count =0; }
     void L_Romate( Tree *&x );
     void R_Romate( Tree *&x );
     void splay( Tree *&x );
     void Insert( int &number );
     int findMax( Tree *T );    
     int findMin( Tree *T );
     Tree *find( int& number ,Tree *T);
     int opt( int &number );
     int min( int a,int b )
     { return a<b? a:b;}
};
void Splay::L_Romate( Tree *&x )
{
      Tree *y = x -> father , *z = y->father;
      y -> rchild = x -> lchild;
      x -> lchild = y;
      if( y -> rchild ) y -> rchild -> father = y;
      y->father = x;
      x -> father = z;
      if( z )
      {
       if( z->lchild == y ) z->lchild = x;
       else z -> rchild = x;        
    }
}
void  Splay::R_Romate( Tree *&x )
{
    Tree *y = x -> father ,*z = y -> father;
    y -> lchild = x -> rchild ;
    x -> rchild =  y;
    if( y -> lchild ) y->lchild -> father =  y;
    x -> father = z;y -> father = x;
    if( z )
    {
       if( z -> lchild == y ) z -> lchild = x;
       else z -> rchild = x;    
    }    
}
void Splay::splay( Tree *&x )
{
    while( x -> father )
    {
       Tree *y = x -> father ,*z = y -> father;
       if( !z )
       {
          if( y->lchild == x ) R_Romate( x );
          else L_Romate( x );        
       }
       else
       {
           if( z -> lchild == y&& y->lchild == x )
           {
               R_Romate( y );
               R_Romate( x );        
           }        
           else
           {
               if( z -> rchild == y && y->rchild ==x )
               {
                   L_Romate( y );
                   L_Romate( x );        
               }        
               else
               {
                 if( z -> rchild == y && y -> lchild == x )
                 {
                      R_Romate( x );
                      L_Romate( x );        
                 }
                 else
                 {
                     L_Romate( x );
                     R_Romate( x );        
                 }         
               }
           }
       }    
    }
    root = x;
    root -> father = NULL;    
}
void Splay::Insert( int &number )
{
   if( !count )
   {
      root = new Tree( number );        
   }    
   else
   {
      Tree *p = find( number ,root ),*q;
      if( p -> num == number )
      {
            p -> cnt++;
            q = p;        
       }
       else
      {
           if( p -> num > number )
           {
              p->lchild = new Tree( number );
              p->lchild->father = p;
              q = p->lchild ;        
           }        
          else
          {
              p -> rchild = new Tree( number );
              p -> rchild -> father = p;
              q = p -> rchild;        
          }
      }
      splay( q );
   }
   count++;
}
Tree *Splay::find( int &number,Tree *T )
{
      if( T && T -> num == number ) return T;
      else
      {
       if( T -> num > number && T -> lchild )
         return find( number , T -> lchild );
       else
       {
            if( T -> num < number && T -> rchild )
                return find( number , T -> rchild );
            else return T;        
       }
     }    
}
int Splay::findMax( Tree *T )
{
     if( T && T->rchild )
        return findMax( T -> rchild );
    if( T )
        return T->num;
    return 0x7fffffff;
    
}
int Splay::findMin( Tree *T )
{
   if( T && T->lchild )
        return findMin( T->lchild );
    if( T )
        return T->num;
    return 0x7fffffff;
}

int Splay::opt( int &number )
{
    
     if( root->lchild == NULL && root->rchild == NULL )
        return abs(root->num);
     if( root->cnt ) return 0;
    int a,b,c = root->num;
//    printf( "root = %d\n",root->num );
    a = findMax( root->lchild );
    b = findMin( root->rchild );
//    printf( "%d %d\n",a,b );
    return min( abs(c-a),abs(c-b) );

}
int main( )
{
   int n,m,sum;
   while( scanf( "%d" ,&n )==1 )
   {
      Splay rt;
      sum = 0;
      for( int i=0 ; i< n; i++ )
      {
         m=0;
         scanf( "%d" ,&m );
         rt.Insert( m );
         sum += rt.opt( m );
//         printf( "sum==%d\n",sum );        
      }
      printf( "%d\n",sum );
   }
   return 0;    
}