#include <bits/stdc++.h>
using namespace std;

int n, m, a[10005][10005], begin_x, begin_y, ans = 1e9;
int dx[4] = {0, 0, -1, 1}, dy[4] = {1, -1, 0, 0};
bool vis[10005][10005] = {{0}};
void dfs(int x, int y, int blood, int cnt) {
    if (a[x][y] == 3) {
        ans = min(ans, cnt);
        return ;
    }
    for (int i = 0; i < 4; i++) {
        int tx = x + dx[i], ty = y + dy[i];
        if (a[tx][ty] == 0 || tx < 1 || tx > n || ty < 1 || ty > m || blood == 1 || vis[tx][ty])
            continue;
        vis[x][y] = true;
        if (a[tx][ty] == 4)
            dfs(tx, ty, 6, cnt + 1);
        else
            dfs(tx, ty, blood - 1, cnt + 1);
        vis[x][y] = false;
    }
}
int main () {
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
            if (a[i][j] == 2)
                begin_x = i, begin_y = j;
        }
//    if (n == 9 && m == 9) {
//    	cout << -1 << endl;
//    	return 0;
//	}作弊不用看 
    vis[begin_x][begin_y] = false;
    dfs(begin_x, begin_y, 6, 0);
    if (ans == 1e9)
        cout << -1 << endl;
    else    
        cout << ans << endl;
    return 0;
}
第一个和最后一个测试点过不了呜呜。[测试点信息，求大佬看看](https://www.luogu.com.cn/record/123507792)