```cpp
#include <bits/stdc++.h>
using namespace std;
const int N = 10;
int g[N][N],n,m,cnt;
int sx,sy,ex,ey;
bool st[N][N];
int dx[4] = {1,-1,0,0}, dy[4] = {0,0,1,-1};
void dfs(int x, int y)
{
if (x == ex && y == ey)
{
cnt ++;
return;
}
for (int i = 0; i < 4; i++)
{
int nex = x + dx[i], ney = y + dy[i];
if (nex >= 1 && ney >= 1 && nex <= n && ney <= m && g[nex][ney] == 0 && !st[nex][ney])
{
//x = nex, y = ney;
st[nex][ney] = true;
dfs(nex,ney);
st[nex][ney] = false;
}
}
return;
}
int main()
{
int t;
cin >> n >> m >> t;
cin >> sx >> sy >> ex >> ey;
while (t--)
{
int i,j;
cin >> i >> j;
g[i][j] = 1;
}
st[sx][sy] = true;
dfs(sx,sy);
cout << cnt << endl;
return 0;
}
```
这是ac了的代码
by Arrosw @ 2022-11-11 20:29:06
第一份代码把x和y改动了，另外3个方向的x和y就不一样了
by liuxy1234 @ 2022-11-11 20:32:22
因为回溯后x和y的值变掉了：
```
for (int i = 0; i < 4; i++)
{
int nex = x + dx[i], ney = y + dy[i];
if (nex >= 1 && ney >= 1 && nex <= n && ney <= m && g[nex][ney] == 0 && !st[nex][ney])
{
//x = nex, y = ney;
st[nex][ney] = true;
dfs(nex,ney);
st[nex][ney] = false;
}
}
```
回溯回来后的循环有用x、y给nex、ney赋值，用的应该是原来的x和y的值呀
by 6k823 @ 2022-11-11 20:32:54
@[Hua_er](/user/823061)
小笨蛋，快来看
by 王茗仟 @ 2022-11-11 21:04:34
啊啊啊明白了，谢谢各位
by Arrosw @ 2022-11-12 08:30:40