要判断外面一圈
------------
0 0 0 1 1
------------
0 0 1 1 0
------------
0 1 0 0 0
------------
1 0 0 0 0
------------
用你的代码就错了
------------
从0 0开始dfs
by MONED @ 2022-08-09 11:07:02
我给的样例不用在意
by MONED @ 2022-08-09 11:10:36
你要是在不会 代码奉上
```cpp
#include <bits/stdc++.h>
using namespace std;
const int K=35;
int n,dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
bool b1[K][K],b2[K][K];
void dfs(int x,int y)
{
if(x<0 || y<0 || x>n+1 || y>n+1 || !b2[x][y]) return;
b2[x][y]=0;
for(int i=0;i<4;++i) dfs(x+dx[i],y+dy[i]);
}
int main(){
cin>>n;
for(int i=1;i<=n;++i) for(int j=1;j<=n;++j) cin>>b1[i][j];
for(int i=0;i<=n+1;++i) for(int j=0;j<=n+1;++j) b2[i][j]=!b1[i][j];
dfs(0,0);
for(int i=1;i<=n;++i)
{
for(int j=1;j<=n;++j)
{
if(b2[i][j]) cout<<2<<" ";
else cout<<b1[i][j]<<" ";
}
cout<<endl;
}
return 0;
}
```
by MONED @ 2022-08-09 11:14:38
@[MONED](/user/715593) 懂了，谢谢
by shipeiqian @ 2022-08-09 11:23:45