O1444 【基础】填涂颜色

#include<bits/stdc++.h>
using namespace std;
int n,cnt,a[101][101];
int dx[]{0,1,-1,0,0};
int dy[]{0,0,0,1,-1};
struct node{
	int x,y;
};
bool check(int x,int y){
	if(a[x][y] != 0)return false;
	if(x < 1 || y < 1 || x > n || y > n)return false;
	return true;
}
void bfs(int x,int y){
	queue<node> q;
	q.push((node){x,y});
	a[x][y]=2;
	while(!q.empty()){
		node t=q.front();
		int nx=t.x;
		int ny=t.y;
		q.pop();
		for(int i = 1;i <= 4;i++){
			int X=nx+dx[i];
			int Y=ny+dy[i];
			if(check(X,Y)){
//				cout << X << " " << Y<< endl;//
				q.push((node){X,Y});
				a[X][Y] = 2;
			}
		}
	}
	
}
signed main(){
	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(i == n || j == n || i == 1 || j == 1){
				if(a[i][j] == 0){
					bfs(i,j);
				}
			}
		}
	}
	for(int i = 1;i <= n;i++){
		for(int j = 1;j <= n;j++){
			if(a[i][j] == 2){
				cout << 0 << " ";
			}
			if(a[i][j] == 1){
				cout << 1 << " ";
			}
			if(a[i][j] == 0){
				cout << 2 << " ";
			}
		}
		cout << endl;
	}
	return 0;
}
/*
6
0 0 0 0 0 0
0 0 1 1 1 1
0 1 1 0 0 1
1 1 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

*/