第二题20分钟查不出错来，竟然坑在了字符串读入上，真服了~~

scanf(“%s”, str[i] + 1)是为了从下标为1读入！！记住呜呜！！

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;
const int N = 20;
bool st[N][N][N];
int k,n,m;
char g[N][N][N];  
int a,b;
struct Point
{
    int x,y,z;
};
int bfs(Point start,int &ans)
{

     queue<Point>q;
     q.push(start);
    st[start.x][start.y][start.z] = true;

    while (q.size())   
    {    
        Point t=q.front();  
        q.pop();
        int dx[6]={1,-1,0,0,0,0},dy[6]={0,0,1,-1,0,0},dz[6]={0,0,0,0,1,-1};  
        for (int i=0;i<6;i++)  
        {
            int x=t.x+dx[i];
            int y=t.y+dy[i];
            int z=t.z+dz[i];
            if (x<1||x>k||y<1||y>n||z<1||z>m) continue;
            if (g[x][y][z]=='#') continue; 
            if (st[x][y][z]) continue; 
            ans++;
            st[x][y][z]=true;

            q.push({x,y,z});
        }
    }

}
int main()
{
    cin>>k>>n>>m;
    for (int i=1;i<=k;i++)
        for (int j=1;j<=n;j++)
           scanf("%s",g[i][j]+1);   # g[i][j]+1 是为了下标为1读入！！

    cin>>a>>b;
    Point start = {1,a,b};
    int ans = 1;

    bfs(start,ans);
    cout<<ans<<endl;
    return 0;
}