HDU-1892 See you~

二维树状数组的模板题了，初始化的时候注意下，不用逐个插入，而是直接用lowbit这个函数。

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#define MAX 1005

int c[MAX][MAX];;

inline int lowbit( int x )
{
    return x & -x;    
}

inline void modify( int x, int y, int val )
{
    for( int i = x; i <= 1001; i += lowbit( i ) )
    {
        for( int j = y; j <= 1001; j += lowbit( j ) )
            c[i][j] += val;
    }    
}

inline int getsum( int x, int y )
{
    int sum = 0;
    for( int i = x; i > 0; i -= lowbit( i ) )
    {
        for( int j = y; j > 0; j -= lowbit( j ) )
            sum += c[i][j];
    }
    return sum;
}

inline void swap( int &x, int &y )
{
    int temp = x;
    x = y;
    y = temp; 
}
  
inline int finalsum( int x1, int y1, int x2, int y2 )
{
    return getsum(x2, y2)-getsum(x1-1, y2)-getsum(x2, y1-1)+getsum(x1-1, y1-1);    
}

inline void getint( int &t ) 
{ 
    char c; 
    while( c= getchar(), c< '0'|| c> '9' ) ; 
    t= c- '0'; 
    while( c= getchar(), c>= '0'&& c<= '9' ) 
    { 
        t= t* 10+ c- '0'; 
    } 
}
  
int main(  )
{
    int T, N, x1, y1, x2, y2, val, sum;
    char op[10];
    getint( T );
    for( int cas = 1; cas <= T; ++cas )
    {
        printf( "Case %d:\n", cas );
        
        for( int i = 1; i <= 1001; ++i )
        {
            for( int j = 1; j <= 1001; ++j )
            {
                c[i][j] = lowbit( i ) * lowbit( j ); 
            }    
        }
        
        scanf( "%d", &N );
        while( N-- )
        {
            scanf( "%s", op );
            if( op[0] == 'A' )
            {
            //    scanf( "%d%d%d", &x1, &y1, &val );
                getint( x1 ), getint( y1 ), getint( val );
                x1++, y1++;
                modify( x1, y1, val );
            }
            else if( op[0] == 'D' )
            {
            //    scanf( "%d%d%d", &x1, &y1, &val );  
                getint( x1 ), getint( y1 ), getint( val );  
                x1++, y1++;
                sum = finalsum( x1, y1, x1, y1 );
                if( val > sum )
                    val = sum;
                modify( x1, y1, -val );
            }
            else if( op[0] == 'M' )
            {
            //    scanf( "%d%d%d%d%d", &x1, &y1, &x2, &y2, &val );
                getint( x1 ), getint( y1 );
                getint( x2 ), getint( y2 ), getint( val );
                x1++, y1 ++, x2++, y2++;
                sum = finalsum( x1, y1, x1, y1 );
                if( val > sum )
                    val = sum;
                modify( x1, y1, -val );
                modify( x2, y2, val );    
            }
            else 
            {
            //    scanf( "%d%d%d%d", &x1, &y1, &x2, &y2 );
                getint( x1 ), getint( y1 );
                getint( x2 ), getint( y2 );
                x1++, y1++, x2++, y2++;
                if( x1 > x2 )   swap( x1, x2 );
                if( y1 > y2 )   swap( y1, y2 );
                printf( "%d\n", finalsum( x1, y1, x2, y2 ) );    
            }
        }
    }  
    return 0;  
}