```#include<iostream>
#include<string.h>
#include<queue>
#define MAXN 50
using namespace std;
int m[MAXN][MAXN],l,d[4][2]={0,1,1,0,0,-1,-1,0};
bool vis[MAXN][MAXN];
queue<pair<int,int> >q;
int main(){
cin>>l;
for(int i=1;i<=l;i++)
for(int j=1;j<=l;j++)
cin>>m[i][j];
q.push(make_pair(0,0));
while(!q.empty()){
int x=q.front().first;
int y=q.front().second;
q.pop();
if(m[x][y]==0)m[x][y]=3;
for(int k=0;k<4;k++){
int xx=x+d[0][k],yy=y+d[1][k];
if(xx<=l+1 && yy<=l+1 && xx>=0 && yy>=0 && m[xx][yy]==0){
q.push(make_pair(xx,yy));
m[xx][yy]=3;
}
}
}
bool c=false;
for(int i=1;i<=l;i++){
for(int j=1;j<=l;j++)
if(m[i][j]==0){
q.push(make_pair(i,j));
//cout<<i<<" "<<j<<endl;
c=true;
break;
}
if(c)break;
}
while(!q.empty()){
int x=q.front().first;
int y=q.front().second;
q.pop();
if(m[x][y]==0)m[x][y]=2;
for(int k=0;k<4;k++){
int xx=x+d[0][k],yy=y+d[1][k];
if(xx<=l && yy<=l && xx>=1 && yy>=1 && m[xx][yy]==0){
q.push(make_pair(xx,yy));
m[xx][yy]=2;
}
}
}
//cout<<endl;
for(int i=1;i<=l;i++){
for(int j=1;j<=l;j++){
if(m[i][j]==3)cout<<"0 ";
else cout<<m[i][j]<<" ";
//cout<<m[i][j]<<" ";
}
cout<<endl;
}
return 0;
}
```
by ZYuhang @ 2019-04-04 21:52:43
$\text{敢问您的头文件库为什么没有输入输出流……}$
@[Nvrgiup_yhang](/space/show?uid=169995)
by first_fan @ 2019-04-04 22:09:21
@[Nvrgiup_yhang](/space/show?uid=169995) 要不要了解一下：
```cpp
#include <bits/stdc++.h>
//壮哉我万能库
```
by first_fan @ 2019-04-04 22:10:21
还有，这个状态叫做
$\colorbox {yellow}{CE}$
不叫
$\colorbox {darkviolet}{RE}$
by first_fan @ 2019-04-04 22:12:31
@[first_fan](/space/show?uid=126484) 额其实我是复制代码没粘上
by ZYuhang @ 2019-04-04 22:25:55
@[first_fan](/space/show?uid=126484)
改完的代码AC
```#include<iostream>
#include<string.h>
#include<queue>
#define MAXN 50
using namespace std;
int m[MAXN][MAXN],le,mx[4]={0,1,0,-1},my[4]={1,0,-1,0};
bool vis[MAXN][MAXN];
queue<pair<int,int> >q;
void tu(int l,int a,int b){
while(!q.empty()){
int x=q.front().first;
int y=q.front().second;
q.pop();
if(m[x][y]==0)m[x][y]=b;
for(int k=0;k<4;k++){
int xx=x+mx[k],yy=y+my[k];
if(xx<=l && yy<=l && xx>=a && yy>=a && m[xx][yy]==0){
q.push(make_pair(xx,yy));
m[xx][yy]=b;
}
}
}
}
int main(){
cin>>le;
for(int i=1;i<=le;i++)
for(int j=1;j<=le;j++)
cin>>m[i][j];
q.push(make_pair(0,0));
tu(le+1,0,3);
bool c=false;
for(int i=1;i<=le;i++){
for(int j=1;j<=le;j++)
if(m[i][j]==0){
q.push(make_pair(i,j));
//cout<<i<<" "<<j<<endl;
c=true;
break;
}
if(c)break;
}
tu(le,1,2);
//cout<<endl;
for(int i=1;i<=le;i++){
for(int j=1;j<=le;j++){
if(m[i][j]==3)cout<<"0 ";
else cout<<m[i][j]<<" ";
//cout<<m[i][j]<<" ";
}
cout<<endl;
}
return 0;
}
/*
3
0 1 0
1 0 1
0 1 0
*/
```
by ZYuhang @ 2019-04-04 22:26:28
@[Nvrgiup_yhang](/space/show?uid=169995) 又没粘上
by ZYuhang @ 2019-04-04 22:26:52
$\text{It's my pleasure to help you}$
$:)$
@ Nvrgiup_yhang
by first_fan @ 2019-04-04 22:28:15