1 #include <iostream>  2   3 using namespace std;  4   5 int w, h;   6 int MAP[41][41];  7 int sx, sy, ex, ey;  8 int res;  9 int dx[4] = { 10     1, -1, 0, 0 11 }; 12 int dy[4] = { 13     0, 0, 1, -1 14 };  15  16 int runing(int &x, int &y, int dir) 17 { 18     for(;;) 19     { 20         int nx = x + dx[dir]; 21         int ny = y + dy[dir]; 22         if(nx >= 0 && nx < w && ny >= 0 && ny < h) 23         { 24             if(MAP[ny][nx] == 1) 25             { 26                 return 1; 27             } 28             else if(nx == ex && ny == ey) 29             { 30                 return 0; 31             } 32         } 33         else 34         { 35             return -1; 36         } 37         x = nx; 38         y = ny; 39     } 40 } 41  42 void dfs(int x, int y, int sum) 43 { 44     int nx, ny; 45     //´óÓÚ10£¬¼ôÖ¦  46     if(sum > 10) 47         return ; 48  49  50     //Ëĸö·½Ïò½øÐÐËÑÑ°  51     for(int i = 0; i < 4; ++i) 52     { 53         nx = x + dx[i]; 54         ny = y + dy[i]; 55         if(nx >= 0 && nx < w && ny >= 0 && ny < h) 56         { 57             if(MAP[ny][nx] == 1) 58             { 59                 continue; 60             } 61         } 62         else 63             continue; 64         nx = x; ny = y; 65         int temp = runing(nx, ny, i); 66         //ÍùÕâ¸ö·½ÏòÅöµ½µÄÊÇǽ  67         if(temp == 1) 68         { 69             MAP[ny+dy[i]][nx+dx[i]] = 0; 70             dfs(nx, ny, sum+1); 71             MAP[ny+dy[i]][nx+dx[i]] = 1; 72              73         } 74         //ÍùÕâ¸ö·½Ïò³ö½çÁË  75         else if(temp == -1) 76         { 77             continue; 78         } 79         //ÍùÕâ¸ö·½Ïòµ½´ïÁËÖÕµã  80         else if(temp == 0) 81         { 82              if(res > sum) 83                  res = sum; 84         } 85     } 86      87 }  88  89 void solver() 90 { 91     res = 11; 92     dfs(sx, sy, 1); 93      94 } 95 int main() 96 { 97     while(cin >> w >> h) 98     { 99         if(w == 0 && h == 0)100             break;101         //input102         for(int i = 0; i < h; ++i)103         {104             for(int j = 0; j < w; ++j)105             {106                 cin >> MAP[i][j];107                 if(MAP[i][j] == 2)108                 {109                     sx = j;110                     sy = i;111                 }112                 if(MAP[i][j] == 3)113                 {114                     ex = j;115                     ey = i;    116                 }117             } 118         }119         //solver120         solver();121         //output 122         if(res > 10)123             cout << -1 << endl;124         else125             cout << res << endl; 126     } 127     128     return 0;129 }