C++ :

// luogu-judger-enable-o2
#include<bits/stdc++.h>
using namespace std;
int n,a[31][31],f[31][31];
void dfs(int i,int j){
	if(i<0||i>n+1||j<0||j>n+1||f[i][j]==1) return;
	f[i][j] = 1;
	dfs(i,j+1);
	dfs(i+1,j);
	dfs(i,j-1);
	dfs(i-1,j);
}
int main(){
   int i,j;
   cin>>n;
   for(i=1;i<=n;i++){
		for(j=1;j<=n;j++){
			cin>>f[i][j];
			a[i][j] = f[i][j];
		}
	}
	dfs(0,0);
	for(i=1;i<=n;i++){
		for(j=1;j<=n;j++){
			if(f[i][j]==0) cout<<2<<" ";
			else cout<<a[i][j]<<" ";
		} 
		cout<<endl;
	} 
    return 0;
}