```cpp
#include<bits/stdc++.h>
using namespace std;
int n,a[37][37],cnt,col[37][37],t,vis[37][37];
const int dir[4][2]={
{0,1},
{0,-1},
{1,0},
{-1,0}
};
int head,tail;
struct point{
int x,y;
};
point que[37*37];
bool check(int x,int y){
return x>=1&&x<=n&&y>=1&&y<=n;
}
bool bfs(){
bool flag=true;
while(head<=tail){
point p=que[head];
head++;
for(int i=0;i<4;i++){
point q;
q.x=p.x+dir[i][0];
q.y=p.y+dir[i][1];
if(!check(q.x,q.y)){
flag=false;
}
if(check(q.x,q.y)&&a[q.x][q.y]==0&&!vis[q.x][q.y]){
tail++;
que[tail]=q;
col[q.x][q.y]=cnt;
vis[q.x][q.y]=1;
}
}
}
return flag;
}
int main(){
cin>>n;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
cin>>a[i][j];
}
}
head=1;
tail=0;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
if(vis[i][j]==0&&a[i][j]==0){
head=1;
tail=0;
tail++;
que[tail].x=i;
que[tail].y=j;
cnt++;
vis[i][j]=1;
col[i][j]=cnt;
if(bfs()){
t=cnt;
}
}
}
}
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
if(col[i][j]==t){
a[i][j]=2;
}
}
}
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
cout<<a[i][j]<<" ";
}
cout<<"\n";
}
}
```
by guanzisheng2 @ 2024-08-15 11:09:06
```
#include <bits/stdc++.h>
using namespace std;
const int N = 35;
int g[N][N];
int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, -1, 0, 1};
int n;
void dfs(int x, int y)
{
g[x][y] = 2; //把和边缘连通的0染成2
for(int i = 0; i < 4; i++)
{
int nx = x + dx[i], ny = y + dy[i];
if(nx >= 1 && nx <= n && ny >= 1 && ny <= n && g[nx][ny] == 0)
{
dfs(nx, ny);
}
}
}
int main()
{
cin >> n;
for(int i = 1; i <= n; i++)
for(int j = 1; j <= n; j++)
cin >> g[i][j];
for(int i = 1; i <= n; i++)
for(int j = 1; j <= n; j++)
if((i == 1 || i== n || j == 1 || j == n) && g[i][j] == 0)
dfs(i, j);
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= n; j++)
{
if(g[i][j] == 0) cout << 2;
else if(g[i][j] == 2) cout << 0;
else cout << 1;
cout << " ";
}
cout << endl;
}
return 0;
}
by ZZyangchengzhuo @ 2024-08-15 11:10:06
求关注
by guanzisheng2 @ 2024-08-15 11:10:21
@[xuruizhe150711](/user/1397517) okay
by ZZyangchengzhuo @ 2024-08-15 11:11:17
我的AC code
```
#include<bits/stdc++.h>
using namespace std;
int a[114][114],step=1;
int n,m,d,f;
int fx[6]={0,0,1,0,-1};
int fy[6]={0,1,0,-1,0};
void dfs(int x,int y){
if(x<1||y<1||x>n||y>n||a[x][y]!=0)return;
a[x][y]=2;
dfs(x,y+1);
dfs(x+1,y);
dfs(x,y-1);
dfs(x-1,y);
}
int main(){
ios::sync_with_stdio(0);
cout.tie(0);cin.tie(0);
cin>>n;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
cin>>a[i][j];
}
}
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
if(a[i][j]==1&&d==0){
d=i;
f=j;
}
}
}
dfs(d+1,f+1);
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
cout<<a[i][j]<<" ";
}cout<<endl;
}
}
by 违规用户名K&xs3Z^ @ 2024-08-15 11:15:31
根据你的改 再找到一个点后 应从那个点再进行搜索
```
#include <bits/stdc++.h>
using namespace std;
int n;
int a[35][35], b[35][35];
int kx[5] = {0, 1, -1, 0, 0};
int ky[5] = {0, 0, 0, 1, -1};
void dfs(int x1, int y1){
b[x1][y1] = 3;
for(int i = 1; i <= 4; i++){
int x2 = x1+kx[i];
int y2 = y1+ky[i];
if(x2<=n && y2<=n && x2>0 && y2>0 && b[x2][y2]==0){
dfs(x2,y2);//改动点
}
}
}
int main(){
cin >> n;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
cin >> a[i][j];
b[i][j] = a[i][j];
}
}
for(int i = 1; i <= n; i++){
if(a[i][1] == 0)dfs(i, 1);
if(a[i][n] == 0)dfs(i, n);
}
for(int i = 1; i <= n; i++){
if(a[1][i] == 0)dfs(1, i);
if(a[n][i] == 0)dfs(n, i);
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
if(b[i][j] == 0)a[i][j] = 2;
cout << a[i][j] << " ";
}
cout << endl;
}
}
```
by 违规用户名K&xs3Z^ @ 2024-08-15 11:20:39
@[违规用户名K&xs3Z^](/user/1271316) 感谢！！！十分感谢！！！！！已A
by H_Monkey @ 2024-08-15 18:51:12
@[ZZyangchengzhuo](/user/1271395) 感谢已A
by H_Monkey @ 2024-08-15 18:51:32
@[xuruizhe150711](/user/1397517) 感谢
by H_Monkey @ 2024-08-15 18:51:49
@[H_Monkey](/user/811570) 嗯嗯
by ZZyangchengzhuo @ 2024-08-15 19:00:28