代码如下：

#include <iostream>
#include <queue>
#include <cstring>
using namespace std;
struct s{
    int ax,ay;
};
int n,m;
char a[1005][1005];
bool v[1005][1005];
int lx[16]={1,2,3,4,-1,-2,-3,-4,0,0,0,0,0,0,0,0};
int ly[16]={0,0,0,0,0,0,0,0,1,2,3,4,-1,-2,-3,-4};
int b(int x,int y){
    memset(v,0,sizeof(v));
    v[x][y]=1;
    queue <s> q;
    s it;
    it.ax=x;
    it.ay=y;
    q.push(it);
    while(!q.empty()){
        s h=q.front();
        q.pop();
        for(int i=0;i<16;i++){
            int nx=h.ax+lx[i];
            int ny=h.ay+ly[i];
            if(nx>0 && nx<=n && ny>0 && ny<=n && a[h.ax][h.ay]!=a[nx][ny] && !v[nx][ny]){
                it.ax=nx;
                it.ay=ny;
                q.push(it);
                v[nx][ny]=1;
            }
        }
    }
    int s=0;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(v[i][j])s++;
        }
    }
    return s;
}
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    for(int i=1;i<=m;i++){
        int x,y;
        cin>>x>>y;
        cout<<b(x,y)<<endl;
    }
    return 0;
}