poj3009

#include <iostream>

using namespace std;

int w, h; 
int MAP[41][41];
int sx, sy, ex, ey;
int res;
int dx[4] = {
    1, -1, 0, 0
};
int dy[4] = {
    0, 0, 1, -1
}; 

int runing(int &x, int &y, int dir)
{
    for(;;)
    {
        int nx = x + dx[dir];
        int ny = y + dy[dir];
        if(nx >= 0 && nx < w && ny >= 0 && ny < h)
        {
            if(MAP[ny][nx] == 1)
            {
                return 1;
            }
            else if(nx == ex && ny == ey)
            {
                return 0;
            }
        }
        else
        {
            return -1;
        }
        x = nx;
        y = ny;
    }
}

void dfs(int x, int y, int sum)
{
    int nx, ny;
    //´óÓÚ10£¬¼ôÖ¦ 
    if(sum > 10)
        return ;


    //Ëĸö·½Ïò½øÐÐËÑÑ° 
    for(int i = 0; i < 4; ++i)
    {
        nx = x + dx[i];
        ny = y + dy[i];
        if(nx >= 0 && nx < w && ny >= 0 && ny < h)
        {
            if(MAP[ny][nx] == 1)
            {
                continue;
            }
        }
        else
            continue;
        nx = x; ny = y;
        int temp = runing(nx, ny, i);
        //ÍùÕâ¸ö·½ÏòÅöµ½µÄÊÇǽ 
        if(temp == 1)
        {
            MAP[ny+dy[i]][nx+dx[i]] = 0;
            dfs(nx, ny, sum+1);
            MAP[ny+dy[i]][nx+dx[i]] = 1;
            
        }
        //ÍùÕâ¸ö·½Ïò³ö½çÁË 
        else if(temp == -1)
        {
            continue;
        }
        //ÍùÕâ¸ö·½Ïòµ½´ïÁËÖÕµã 
        else if(temp == 0)
        {
             if(res > sum)
                 res = sum;
        }
    }
    
} 

void solver()
{
    res = 11;
    dfs(sx, sy, 1);
    
}
int main()
{
    while(cin >> w >> h)
    {
        if(w == 0 && h == 0)
            break;
        //input
        for(int i = 0; i < h; ++i)
        {
            for(int j = 0; j < w; ++j)
            {
                cin >> MAP[i][j];
                if(MAP[i][j] == 2)
                {
                    sx = j;
                    sy = i;
                }
                if(MAP[i][j] == 3)
                {
                    ex = j;
                    ey = i;    
                }
            } 
        }
        //solver
        solver();
        //output 
        if(res > 10)
            cout << -1 << endl;
        else
            cout << res << endl; 
    } 
    
    return 0;
}