poj 2019 Cornfields

二位线段树:

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<set>
#include<cstring>
#include<vector>
#include<string>
#define LL long long
using namespace std;
class Node
{
public:
    int l,r,max,min;    
};
class Tree
{
public:
      int l,r;
      Node n[1024];
}T[1024];
int Max,Min;
int map[254][254];
void build_y( Node *p ,int l , int r , int cnt , int s,int e )
{
//     printf( "l==%d r==%d\n",l,r );
     p[cnt].l = l ;p[cnt].r = r;
     if( l == r ) 
     {
         int MAX = -1,MIN = 0x7fffffff;
         for( int i = s ; i <= e ; i ++ )
         {
              MAX = max( MAX , map[i][l] );
              MIN = min( MIN , map[i][l] );        
         }
         p[cnt].min = MIN ;p[cnt].max = MAX;
         return;
     }    
     int mid = ( l + r )>>1;
     build_y( p , l , mid ,cnt*2,s,e );
     build_y( p , mid + 1 , r , cnt*2+1,s,e );
     p[cnt].max = max( p[cnt*2].max , p[cnt*2+1].max );
     p[cnt].min = min( p[cnt*2].min , p[cnt*2+1].min );
//     printf( "%d %d %d %d\n",l,r,p[cnt].max , p[cnt].min );
}
void build( int l, int r , int cnt , int N )
{
     T[cnt].l = l ; T[cnt].r = r;
     build_y( T[cnt].n ,1 , N , 1 ,l ,r );
     if( l == r ) return;
     int mid = ( l + r )>>1;
     build( l , mid , cnt*2 , N );
     build( mid + 1 , r , cnt*2+1 , N );    
}
void Query_y( Node *p ,int l, int r , int cnt )
{
//    printf( "af" );
     if( l <= p[cnt].l && r >= p[cnt].r )
     {
         Max = max( Max , p[cnt].max );
         Min = min( Min , p[cnt].min );
         return;        
     }    
     int mid = ( p[cnt].l + p[cnt].r )>>1;
     if( mid >= r ) Query_y( p , l ,r ,cnt*2 );
     else if( mid < l ) Query_y( p , l , r , cnt* 2 + 1 );
     else
     {
         Query_y( p , l , mid , cnt*2 );
         Query_y( p , mid + 1, r , cnt*2 + 1 );        
     }
}
void Query( int l , int r , int cnt ,int y1 , int y2 )
{
//    printf( "%d %d %d %d %d\n",l,r,cnt,T[cnt].l,T[cnt].r );
     if( l<=T[cnt].l&&r >= T[cnt].r )
     {//printf( "af" );
         Query_y( T[cnt].n ,y1, y2 ,1 );
         return ;        
     }
     int mid = ( T[cnt].l + T[cnt].r )>>1;
     if( mid >= r ) Query( l , r , cnt*2 , y1 , y2 );
     else if( mid < l ) Query( l , r, cnt * 2 + 1, y1, y2 );
     else
     {
          Query( l , mid , cnt*2 , y1 ,y2 );
          Query( mid + 1 , r , cnt*2 +1 , y1 , y2 );        
     }
}
int main(  )
{
    int N,B,K,R,L;
    while( scanf( "%d %d %d",&N,&B,&K )==3 )
    {
        for( int i = 1; i <= N; i ++ )
           for( int j = 1 ; j <= N; j ++ )
                 scanf( "%d",&map[i][j] );
        build( 1 , N ,1 ,N );
        for( int i = 0 ; i < K ; i++ )
        {
            Max = -1 ; Min = 0x7ffffff;
            scanf( "%d %d",&R,&L );
            Query( R , R + B -1, 1 , L , L + B-1 );
//            printf( "%d %d\n",Max ,Min );
            printf( "%d\n",Max - Min );
        }     
    }
    //system( "pause" );
    return 0;
}