DFS---迷宫问题

#include<iostream>
#include<string>
#include<cstring>
using namespace std;//dfs
int flag;
int p[];
int a[][];
void Dfs(int n,int m)//起点,终点
{
    if (n == m)
    {
        flag = ;
        return;
    }
    for (int i = ; i < ; i++)
    {
        if (a[n][i] && !p[a[n][i]])
        {
            p[a[n][i]] = ;
            Dfs(a[n][i], m);
            p[a[n][i]] = ;//???
        }
    }
}
int main()
{
    int n;
    int m;
    while (cin >> n && n != )
    {
        flag = ;
        for (int i = ; i <=n;i++)
        {
            for (int j = ; j < ; j++)
            {
                cin >> a[i][j];
            }
        }
        cin >> m;//代表终点
        p[] = ;//起点访问过
        Dfs(,m);
        if (flag == )
            cout << "YES" << endl;
        else
            cout << "NO" << endl;

    }
    return ;
}