@[ImopsterAnYu](/user/510555) 确实没看懂您怎么写的
```cpp
#include<bits/stdc++.h>
using namespace std;
int a,b,c,d,n,ans=1e7,vis[1005][1005];
char s[1005][1005];
struct node{
int a,b,c;
};
void bfs(){
queue<node> q;
q.push(node({a,b,0}));
while(!q.empty()){
int x=q.front().a,y=q.front().b,t=q.front().c;
q.pop();
if(x<1||x>n||y<1||y>n||s[x][y]=='1'||t>=ans)
continue;
if(vis[x][y]!=-1&&t>=vis[x][y])
continue;
vis[x][y]=t;
if(x==c&&y==d){
ans=t;
continue;
}
q.push(node({x-1,y,t+1}));
q.push(node({x+1,y,t+1}));
q.push(node({x,y-1,t+1}));
q.push(node({x,y+1,t+1}));
}
}
int main(){
scanf("%d",&n);
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
cin>>s[i][j],vis[i][j]=-1;
scanf("%d%d%d%d",&a,&b,&c,&d);
bfs();
printf("%d\n",ans);
return 0;
}
```
by qwq___qaq @ 2021-11-05 23:39:13
@[pengzijun](/user/556362) az，谢谢了，我再调一下……
by ImposterAnYu @ 2021-11-05 23:46:15
@[ImopsterAnYu](/user/510555) 我也实在是看不懂，附上丑陋代码
```cpp
#include <bits/stdc++.h>
using namespace std;
struct Nobe {
int x, y, step;
} a[1000005];
char q[1005][1005];
bool flag[1005][1005];
int n, sx, sy, zx, zy;
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};
int bfs(int sx, int sy) {
int head = 1, tail = 1;
a[tail].x = sx;
a[tail].y = sy;
a[tail].step = 0;
tail++;
flag[sx][sy] = 1;
int nx, ny;
while (1) {
Nobe h = a[head];
if (h.x == zx && h.y == zy) {
return h.step;
}
for (int i = 0; i <= 3; i++) {
nx = h.x + dx[i];
ny = h.y + dy[i];
if (nx >= 1 && nx <= n && ny >= 1 && ny <= n && q[nx][ny] == '0' && flag[nx][ny] == 0) {
a[tail].x = nx;
a[tail].y = ny;
a[tail].step = h.step + 1;
tail++;
flag[nx][ny] = 1;
}
}
head++;
}
}
int main() {
int ans = -1;
cin >> n;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
cin >> q[i][j];
}
}
cin >> sx >> sy >> zx >> zy;
ans = bfs(sx, sy);
cout << ans;
return 0;
}
```
by Chang_Pei @ 2021-11-06 12:53:00