答案

#include<iostream>
#include<queue>
#include<cstring>
using namespace std;
struct node{int x,y,z,step;};
int n,sx,sy,sz,ex,ey,ez;
char mp[25][25][25];
bool vis[25][25][25];
int dx[6]={1,-1,0,0,0,0};
int dy[6]={0,0,1,-1,0,0};
int dz[6]={0,0,0,0,1,-1};
int main(){    
    cin>>n;    
    for(int k=0;k<n;k++){        
    for(int i=0;i<n;i++){            
    for(int j=0;j<n;j++){                
    cin>>mp[k][i][j];                
    if(mp[k][i][j]=='S'){sx=i;sy=j;sz=k;}                
    if(mp[k][i][j]=='E'){ex=i;ey=j;ez=k;}
                }
            }
        }    
    memset(vis,0,sizeof(vis));    
    queue<node>q;    
    q.push({sx,sy,sz,0});    
    vis[sz][sx][sy]=1;    
    int ans=-1;    
    while(!q.empty()){        
    node t=q.front();q.pop();        
    if(t.x==ex&&t.y==ey&&t.z==ez){ans=t.step;break;}        
    for(int i=0;i<6;i++){            
    int nx=t.x+dx[i],ny=t.y+dy[i],nz=t.z+dz[i];            
    if(nx<0||nx>=n||ny<0||ny>=n||nz<0||nz>=n)continue;            
    if(vis[nz][nx][ny])continue;            
    if(mp[nz][nx][ny]=='#')continue;            
    vis[nz][nx][ny]=1;            
    q.push({nx,ny,nz,t.step+1});
            }
        }    
    cout<<ans;    
    return 0;
    }