```
#include<bits/stdc++.h>
using namespace std;
int n,t,sx,sy,tx,ty,cnt,fx,fy;
char np[105][105];
bool mp[105][105];
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};
void dfs(int x,int y){
for(int i=0;i<=3;i++){
int nx=x+dx[i];
int ny=y+dy[i];
if(nx>=1&&nx<=n+2&&ny>=1&&ny<=n+2&&np[nx][ny]=='0'&&mp[nx][ny]==0){
mp[nx][ny]=1;
dfs(nx,ny);
}
}
}
int main(){
cin>>n;
for(int i=2;i<=n+1;i++){
for(int j=2;j<=n+1;j++){
cin>>np[i][j];
}
}
for(int i=1;i<=n+2;i++){
for(int j=1;j<=n+2;j++){
if(np[i][j]==0){
np[i][j]='0';
}
}
}
dfs(1,1);
for(int i=2;i<=n+1;i++){
for(int j=2;j<=n+1;j++){
if(np[i][j]=='0'&&mp[i][j]==0)
np[i][j]='2';
cout<<np[i][j]<<' ';
}
cout<<endl;
}
return 0;
}
```
by Forever1507 @ 2021-01-01 22:25:32