1250：The Castle

题目分析：

  1. 求连通块个数和最大连通块
  2. 十进制转换为四位数的二进制，从左到右依次表示WNES(西北东南)

代码如下：

#include<iostream>
#include<queue>

using namespace std;

#define x first
#define y second
#define pii pair<int,int>
#define el endl

const int N = 55;

int n,m;
int g[N][N];
bool st[N][N];
int dx[4] = {0,-1,0,1};
int dy[4] = {-1,0,1,0};

int bfs(int sx,int sy){
    queue<pii> q;
    q.push({sx,sy});
    st[sx][sy] = true;
    int area = 0;
    while(q.size()){
        pii t = q.front();
        q.pop();
        area ++;
        for(int i = 0; i < 4; i ++ ){
            int a = t.x + dx[i],b = t.y + dy[i];
            if(a < 0 || a > n - 1 || b < 0 || b > m - 1) continue;
            if(st[a][b] || (g[t.x][t.y] >> i) & 1) continue;
            st[a][b] = true;
            q.push({a,b});
        }
    } 
    return area;    
}

int main(){
    cin >> n >> m;
    for(int i = 0; i < n; i ++ )
        for(int j = 0; j < m; j ++ )
            cin >> g[i][j];
    int cnt = 0,area = 0;
    for(int i = 0; i < n; i ++ )
        for(int j = 0; j < m; j ++ )
            {
                if(st[i][j]) continue;
                area = max(area,bfs(i,j));
                cnt ++;
            }
    cout<<cnt<<el<<area<<el;
    return 0;
}