POJ 3009 Curling 2.0

  
    

   
     #include 
   
     <
   
     stdio.h
   
     >
   
     

   
     #define
   
      MAXN 21
   
     

   
     int
   
      map[MAXN][MAXN];

   
     int
   
      startx, starty;

   
     int
   
      w, h, ok, minMove;

   
     int
   
      dr[
   
     4
   
     ][
   
     2
   
     ] 
   
     =
   
      {{
   
     1
   
     ,
   
     0
   
     },{
   
     -
   
     1
   
     ,
   
     0
   
     },{
   
     0
   
     ,
   
     1
   
     },{
   
     0
   
     ,
   
     -
   
     1
   
     }};

   
     int
   
      legal(
   
     int
   
      x, 
   
     int
   
      y){
 
   
     if
   
     (x 
   
     >=
   
      
   
     1
   
      
   
     &&
   
      y 
   
     >=
   
      
   
     1
   
      
   
     &&
   
      x 
   
     <=
   
      h 
   
     &&
   
      y 
   
     <=
   
      w )
 
   
     return
   
      
   
     1
   
     ;
 
   
     return
   
      
   
     0
   
     ;
}

   
     void
   
      
   
     in
   
     (){
 
   
     int
   
      i, j;
 
   
     for
   
     (i 
   
     =
   
      
   
     1
   
     ; i 
   
     <=
   
      h; 
   
     ++
   
     i){
 
   
     for
   
     (j 
   
     =
   
      
   
     1
   
     ; j 
   
     <=
   
      w; 
   
     ++
   
     j){
 scanf(
   
     "
   
     %d
   
     "
   
     ,
   
     &
   
     map[i][j]);
 
   
     if
   
     (map[i][j] 
   
     ==
   
      
   
     2
   
     ){
 startx 
   
     =
   
      i;
 starty 
   
     =
   
      j;
 map[i][j] 
   
     =
   
      
   
     0
   
     ;
 }
 }
 }
}

   
     void
   
      DFS(
   
     int
   
      x, 
   
     int
   
      y,
   
     int
   
      move){ 
 
   
     int
   
      d,nx,ny; 
 
   
     if
   
     (move 
   
     >=
   
      minMove){ 
 
   
     return
   
     ; 
 } 
 
   
     for
   
     (d 
   
     =
   
      
   
     0
   
     ; d 
   
     <
   
      
   
     4
   
     ; d
   
     ++
   
     ){ 
 nx 
   
     =
   
      x; 
 ny 
   
     =
   
      y; 
 
   
     while
   
     (
   
     1
   
     ){ 　　//要注意的地方
 nx 
   
     +=
   
      dr[d][
   
     0
   
     ]; 
 ny 
   
     +=
   
      dr[d][
   
     1
   
     ]; 
 
   
     if
   
     ( 
   
     !
   
     legal(nx, ny) 
   
     ||
   
      map[nx][ny] 
   
     ==
   
      
   
     1
   
     ){ 
 　　
   
     break
   
     ; 
 } 
 
   
     if
   
     (map[nx][ny] 
   
     ==
   
      
   
     0
   
      
   
     &&
   
      map[nx
   
     +
   
     dr[d][
   
     0
   
     ]][ny
   
     +
   
     dr[d][
   
     1
   
     ]] 
   
     ==
   
      
   
     1
   
     ){ 
 map[nx
   
     +
   
     dr[d][
   
     0
   
     ]][ny
   
     +
   
     dr[d][
   
     1
   
     ]] 
   
     =
   
      
   
     0
   
     ; 
 　　　　 DFS(nx,ny,move
   
     +
   
     1
   
     ); 
 map[nx
   
     +
   
     dr[d][
   
     0
   
     ]][ny
   
     +
   
     dr[d][
   
     1
   
     ]] 
   
     =
   
      
   
     1
   
     ; 
 
   
     break
   
     ; 
 } 
 
   
     if
   
     (map[nx][ny] 
   
     ==
   
      
   
     3
   
     ){ 
 
   
     if
   
     (move 
   
     <
   
      minMove){ 
 minMove 
   
     =
   
      move; 
 ok 
   
     =
   
      
   
     1
   
     ;
 
   
     break
   
     ;
 } 
 } 
 } 
 } 
 
}

   
     int
   
      main(){
 
 
   
     int
   
      i, j;
 
   
     while
   
     (scanf(
   
     "
   
     %d%d
   
     "
   
     ,
   
     &
   
     w, 
   
     &
   
     h) 
   
     ==
   
      
   
     2
   
     , w 
   
     +
   
      h){
 memset(map, 
   
     0
   
     , 
   
     sizeof
   
     (map));
 
   
     in
   
     ();
 ok 
   
     =
   
      
   
     0
   
     ;
 minMove 
   
     =
   
      
   
     11
   
     ;
 DFS(startx, starty,
   
     1
   
     ); 
 
   
     if
   
     ( ok )
 printf(
   
     "
   
     %d\n
   
     "
   
     ,minMove); 
 
   
     else
   
     
 printf(
   
     "
   
     -1\n
   
     "
   
     );
 }
 
   
     return
   
      
   
     0
   
     ;
}