bzoj1193

#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<queue>
using namespace std ; 

int d [ 100 ] [ 100 ] ;
int ha ( const int x , const int y ) {
    if ( x == 0 && y == 0 ) return 0 ;
    typedef pair < int , int > p ;
    queue < p > q ;
    for ( int i = 0 ; i < 100 ; ++ i ) 
         for ( int y = 0 ; y < 100 ; ++ y ) d [ i ] [ y ] = - 1 ;
    d [ 50 ] [ 50 ] = 0 ;
    q . push ( make_pair ( 50 , 50 ) ) ;
    while ( q . size () ) {
        const p o = q . front () ; q . pop () ;
        if ( abs ( o . first - 50 ) > 40 || abs ( o . second - 50 ) > 40 ) continue ;
        const int x_ [] = { 1 , 1 , 2 , 2 , -2 , -2 , -1 , -1 } ;
        const int y_ [] = { 2 , -2 , 1 , -1 , 1 , -1 , 2 , -2 } ;  
        for ( int i = 0 ; i < 8 ; ++ i ) {
            const int nx = o . first + x_ [ i ] ;
            const int ny = o . second + y_ [ i ] ;
            if ( nx == x + 50 && ny == y + 50 ) return d [ o . first ] [ o . second ] + 1 ;
            if ( d [ nx ] [ ny ] == - 1 ) {
                d [ nx ] [ ny ] = d [ o . first ] [ o . second ] + 1 ;
                q . push ( make_pair ( nx , ny ) ) ;
            }
        }
    }
    exit ( -1 ) ;
}

int xp , yp , xs , ys ; 
int x , y ; 
int step_cnt = 0 ;
int main () {
    scanf ( "%d%d%d%d" , & xp , & yp , & xs , & ys ) ;
    x = abs ( xp - xs ) ; y = abs ( yp - ys ) ;
    while ( abs ( x ) + abs ( y ) >= 30 ) {
        if ( abs ( x ) >= abs ( y ) ) {
            const int step = abs ( x / 6 ) ;
            x -= ( ( x > 0 ) ? step : - step ) * 2 ;
            y -= ( y > 0 ) ? step : - step ;
            step_cnt += abs ( step ) ;
        } else {
            const int step = abs ( y / 6 ) ;
            x -= ( x > 0 ) ? step : - step ;
            y -= ( y > 0 ? step : - step ) * 2 ;
            step_cnt += abs ( step ) ;
        }
    }
    printf ( "%d
" , step_cnt + ha ( abs ( x ) , abs ( y ) ) ) ;
    return 0 ;
}

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