算法1

C++ 代码

#include<iostream>
#include<cstdio>
#include<algorithm>

using namespace std;

#define x first
#define y second

typedef pair<int,int> PII;

const int N=1010;

int n;
char g[N][N];
bool st[N][N];
PII q[N*N];

int dx[4]={-1,0,1,0};
int dy[4]={0,1,0,-1};
void bfs(int sx,int sy,int &total ,int &bound){
    int hh=0,tt=0;
    q[0]={sx,sy};
    st[sx][sy]=true;

    while(hh<=tt){
        PII t=q[hh++];
        total++;

        bool is_bound=false;
        for(int i=0;i<4;i++){

            int x=t.x+dx[i],y=t.y+dy[i];
            if(x<0||x>=n ||y<0 ||y>=n)continue;
            if(st[x][y])continue;
            if(g[x][y]=='.'){
                is_bound=true;
                continue;
            }

            q[++tt]={x,y};
            st[x][y]=true;

        }

        if(is_bound)bound++;


    }





}



int main(){

  scanf("%d",&n);
  for(int i=0;i<n;i++)scanf("%s",g[i]);

  int cnt=0;
  for(int i=0;i<n;i++){
      for(int j=0;j<n;j++)
      {
          if(!st[i][j] && g[i][j]=='#'){
              int total =0,bound=0;
              bfs(i,j,total,bound);
              if(total==bound) cnt++;
          }
      }
  }
   printf("%d",cnt); 
    return 0;
}