3009

#include <iostream>#include <cstring>using namespace std;int w, h, sx, sy, gx, gy, direction[4][2] = {{0, -1}, {1, 0}, {0, 1}, {-1, 0}}, ans, step;char map[20][21];int init(){cin >> w >> h;for(int i = 0; i < h; ++i){for(int j = 0; j < w; ++j){cin >> map[i][j];}}for(int i = 0, j; i < h; ++i){for(j = 0; j < w && map[i][j] != '2'; ++j);if('2' == map[i][j]){sy = i;sx = j;break;}}for(int i = 0, j; i < h; ++i){for(j = 0; j < w && map[i][j] != '3'; ++j);if('3' == map[i][j]){gy = i;gx = j;break;}}return w + h;}void dfs(const int cx, const int cy){for(int i = 0; i < 4; ++i){int tx = cx + direction[i][0], ty = cy + direction[i][1], stepnum;if(tx >= 0 && tx < w && ty >= 0 && ty < h && map[ty][tx] != '1'){switch(i){case 0: stepnum = cy; break;case 1: stepnum = w - 1 - cx; break;case 2: stepnum = h - 1 - cy; break;default: stepnum = cx;}for(; stepnum && map[ty][tx] != '1' && map[ty][tx] != '3'; --stepnum, tx += direction[i][0], ty += direction[i][1]);if(stepnum){if('3' == map[ty][tx]){++step;ans = (step < ans)? step: ans;--step;}else if('1' == map[ty][tx]){++step;if(step < ans){map[ty][tx] = '0';dfs(tx - direction[i][0], ty - direction[i][1]);map[ty][tx] = '1';}--step;}}}}}int main(){while(init()){ans = 11;step = 0;dfs(sx, sy);cout << ((ans > 10)? -1: ans) << endl;memset(map, 0, sizeof(map));}return 0;}