POJ3009.cpp

#include <iostream>
#include <algorithm>
#include <utility>
#include <map>
#include <queue>
#include <string>
#include <vector>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <ctime>
#include <cmath>

using namespace std;

#define FOR(i, j, k) for(int i = j; i < k; ++i)
#define rep(i, j) FOR(i, 0, j)
#define INF (1 << 30)
#define fi first
#define se second

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> Pi;
typedef pair<P, P> PP;

const int MOD = 1e9 + 7;
const int dy[]={0, 0, 1, -1};
const int dx[]={1, -1, 0, 0};

template <class T> void chmin(T& a, const T& b) { a = min(a, b); }
template <class T> void chmax(T& a, const T& b) { a = max(a, b); }

int w, h;
int field[20][20];
int sx, sy, res = INF;

void dfs(int x, int y, int cnt) {
    if(cnt + 1 > 10) return;
    rep(i, 4) {
        int nx = x + dx[i], ny = y + dy[i];
        if(nx < 0 || nx >= w || ny < 0 || ny >= h || field[ny][nx] == 1) {
            continue;
        }
        while(1) {
            if(nx < 0 || nx >= w || ny < 0 || ny >= h || field[ny][nx] == 1) break;
            if(field[ny][nx] == 3) {
                chmin(res, cnt + 1);
                return;
            }
            nx += dx[i]; ny += dy[i];
        }
        if(0 <= nx && nx < w && 0 <= ny && ny < h) {
            field[ny][nx] = 0;
            dfs(nx - dx[i], ny - dy[i], cnt + 1);
            field[ny][nx] = 1;
        }
    }
}

signed main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    while(scanf("%d %d", &w, &h), w | h) {
        rep(i, h) rep(j, w) {
            scanf("%d", &field[i][j]);
            if(field[i][j] == 2) {
                sx = j; sy = i;
            }
        }
        res = INF;
        dfs(sx, sy, 0);
        printf("%d\n", (res != INF) ? res : -1);
    }
    return 0;
}