题解！！！

#include <bits/stdc++.h>
using namespace std;
int n,m,flag;
int mp[50][50];
int vis[50][50];
void bfs(int x, int y){
    if(x == n && y == m){
        flag = 1;
        return ;
    }
    int newx, newy;
    newx = x - 1, newy = y;
    if(mp[newx][newy] == 0 && newx >= 1 && newx <= n && newy >= 1 && newy <= m && vis[newx][newy] == 0){
        vis[newx][newy] = 1;
        bfs(newx,newy);
    }
    newx = x + 1, newy = y;
    if(mp[newx][newy] == 0 && newx >= 1 && newx <= n && newy >= 1 && newy <= m && vis[newx][newy] == 0){
        vis[newx][newy] = 1;
        bfs(newx,newy);
    }
    newx = x, newy = y + 1;
    if(mp[newx][newy] == 0 && newx >= 1 && newx <= n && newy >= 1 && newy <= m && vis[newx][newy] == 0){
        vis[newx][newy] = 1;
        bfs(newx,newy);
    }
    newx = x, newy = y - 1;
    if(mp[newx][newy] == 0 && newx >= 1 && newx <= n && newy >= 1 && newy <= m && vis[newx][newy] == 0){
        vis[newx][newy] = 1;
        bfs(newx,newy);
    }
    
    
}
int main(){
    cin >> n >> m;
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++) cin >> mp[i][j];
    }
    bfs(1,1);
    if(flag) cout << "YES";
    else cout << "NO";
    
    return 0;
}

懒得写注释了，自己理解吧