code:

#include<bits/stdc++.h>

using namespace std;
char c[1010][1010];
int n,m,ans=0;
int tx,ty;
int dx[]={0,0,1,0,-1};
int dy[]={0,1,0,-1,0};//方向数组
void dfs(int x,int y){
    
    for(int i=1;i<=4;i++){
        tx=x+dx[i];
        ty=y+dy[i];
        if(tx>=1&&tx<=n&&ty>=1&&ty<=m&&c[tx][ty]=='#'){
            c[tx][ty]='k';
            dfs(tx,ty);//有#就dfs，并且将自己设为一个不是#的字符
        }
    }

}
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>c[i][j];
        }
    }//输入
    int x,y;
    for(int i=1;i<=n+1;i++){
        for(int j=1;j<=m+1;j++){
            x=i;
            y=j;
            if(c[x][y]=='.'&&c[x-1][y]=='#'&&c[x][y+1]=='#'&&c[x-1][y+1]=='#'){
                cout<<"Bad placement.";
                exit(0);
            }
            if(c[x][y]=='#'&&((c[x-1][y]=='#'&&c[x][y+1]=='#'&&c[x-1][y+1]=='.')||(c[x-1][y]=='.'&&c[x][y+1]=='#'&&c[x-1][y+1]=='#')||(c[x-1][y]=='#'&&c[x][y+1]=='.'&&c[x-1][y+1]=='#'))){
                cout<<"Bad placement.";
                exit(0);
            }//判断是否可以组成航母
            if(c[i][j]=='#'){
                dfs(i,j);
                ans++;//dfs可以组成航母的连通块
            }
        }
    }
   cout<<"There are "<<ans<<" ships.";
   //输出
    return 0;
}

码风很丑，望大佬见谅。