Prison Break

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

int data[21][21];

int dfs(int u,int v,int n){
    int ans = 0;

    if( u == n and v == n) return 1;
    data[u][v] = 1;
    if(u - 1 >= 1 and data[u-1][v] == 0)
         ans += dfs(u-1,v,n);
    if(v - 1 >= 1 and data[u][v-1] == 0)
         ans += dfs(u,v-1,n);
    if(u+1 <= n and data[u+1][v] == 0)
         ans += dfs(u+1,v,n);
    if(v+1 <= n and data[u][v+1] == 0)
         ans += dfs(u,v+1,n);
    data[u][v] = 0;
 return ans ;
}
int main()
{
    freopen("in.txt","r",stdin);
    int n, t;
    cin >> t;
    while(t--){
    cin >> n;

    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= n; j++)
           cin >> data[i][j];

    if(data[1][1] == 1 and data[n][n] == 1) cout << 0 << endl;
    else cout << dfs(1,1,n) << endl;

    }
    return 0;
}