学步园

#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;
}