我来发题解啦

#include <bits/stdc++.h>
 
using namespace std;
 
int n, s;
bool b[13][13];
const int dx[8] = {0, 0, 1, 1, 1, -1, -1, -1};
const int dy[8] = {1, -1, 1, 0, -1, 1, 0, -1};
 
void go(int x, int y){
	if(x == 1 && y == n){
		s++;
		return;
	}
	int xx, yy;
	for(int i = 0; i <= 7; i++){
		xx = x + dx[i];
		yy = y + dy[i];
		if(b[xx][yy]){
			b[xx][yy] = false;
			go(xx, yy);
			b[xx][yy] = true;
		}
	}
}
 
int main(){
	int x;
	cin >> n;
	memset(b, 0, sizeof(b));
	for(int i = 1; i <= n; i++){
	  	for(int j = 1; j <= n; j++){
			cin >> x;
			b[i][j] = (x == 0);
		}
	}
	s = 0;
	b[1][1] = false;
	go(1, 1);
    cout << s << endl;
    return 0;
}

已AC！