#include <bits/stdc++.h>
using namespace std;
int arr[12][12];
int n, m, min123 =999;
void dfs(int x, int y, int times, int hp){
    if(hp == 0) return;
    if(x>=n || y>=m || x<0 || y<0) return;
    if(arr[x][y] == 0) return;
    if(arr[x][y] == 3){
        if(times < min123) min123 = times;
        return;
    }
    if(arr[x][y] == 4){
        arr[x][y] = 1;
        dfs(x+1, y, times+1, 5);
        dfs(x-1, y, times+1, 5);
        dfs(x, y+1, times+1, 5);
        dfs(x, y-1, times+1, 5);
        arr[x][y] = 4;
        return;
    }
    dfs(x+1, y, times+1, hp-1);
    dfs(x-1, y, times+1, hp-1);
    dfs(x, y+1, times+1, hp-1);
    dfs(x, y-1, times+1, hp-1);
    return; 
}
int main(){
    cin>> n>> m;
    int startn, startm;
    for(int i=0; i<n; i++){
        for(int j=0; j<m; j++){
            cin>> arr[i][j];
            if(arr[i][j] == 2){
                startm = i;
                startn = j;
                arr[i][j] = 1;
            }
        }
    }
    dfs(startm, startn, 0, 6);
    if(min123 == 999) min123 = -1;
    cout<< min123;
    return 0;
} 
另外想问一下，bits/stdc++.h这个在noip可以使用吗0. 0?