#include<bits/stdc++.h>
using namespace std;
int n,m,cnt=1;
char place[1001][1001];
int place1[1001][1001],book[1001][1001];
int vis[4][2]={1,0,0,1,-1,0,0,-1};
struct S{
	int x,y;
};
queue<S>q;
void bfs(){
	while(!q.empty()){
		for(int i=0;i<4;i++){
		    int xx=q.front().x+vis[i][0];
		    int yy=q.front().y+vis[i][1];
		    if(xx>=1&&xx<=n&&yy>=1&&yy<=n&&book[xx][yy]==0&&place1[xx][yy]!=place1[q.front().x][q.front().y]){
		    	book[xx][yy]=1;
		    	cnt++;
		        q.push({xx,yy});
		    }
		}
		q.pop();
	}
}
int main(){
	ios::sync_with_stdio(0),cin.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			cin>>place[i][j];
			if(place[i][j]=='1')place1[i][j]=1;
			else place1[i][j]=0;//字符转数字 
		}
	}
	while(m--){
		int x,y;
		cin>>x>>y;
		q.push({x,y});
		book[x][y]=1;
		bfs();
		cout<<cnt<<endl;
		memset(book,0,sizeof(book));
		cnt=1;
	}
	return 0;
}

怎么优化呢