#include <bits/stdc++.h>
using namespace std;
int sq[6][6];
int n, m, t;
int bx, by, ex, ey;
int u, v, total;
bool visited[6][6];
int dir[4][2] = {
{1, 0},
{0, 1},
{0, -1},
{-1, 0},
};
void dfs(int x, int y) {
if (x == ex && y == ey) {
++total;
return;
}
for (int i = 0; i < 4; ++i) {
int tx = x + dir[i][0];
int ty = y + dir[i][1];
/*
下面代码改成这个就对了。
if (visited[tx][ty] || sq[tx][ty] == 0) continue;
和
if (visited[tx][ty]==0 && sq[tx][ty] == 1){}
不是逆否命题吗?
if (visited[tx][ty]==0 && sq[tx][ty] == 1) {
visited[x][y] = 1;
dfs(tx, ty);
visited[x][y] = 0;
}*/
if (visited[tx][ty] || sq[tx][ty] == 0) continue;
visited[x][y] = 1;
dfs(tx, ty);
visited[x][y] = 0;
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(nullptr), cout.tie(nullptr);
cin >> n >> m >> t;
cin >> bx >> by >> ex >> ey;
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= m; ++j) sq[i][j] = 1;
while (t--) {
cin >> u >> v;
sq[u][v] = 0;
}
if (sq[ex][ey] == 0) {
cout << "0" << endl;
return 0;
}
dfs(bx, by);
cout << total << endl;
return 0;
}
上面代码为什么在我电脑上就是891,我提交直接AC了呢?
5 5 5
1 2 5 5
2 1
2 2
2 3
2 4
3 4