hdu 2251 Dungeon Master bfs

#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <typeinfo>
#include <fstream>
typedef long long ll;
using namespace std;
//freopen("D.in","r",stdin);
//freopen("D.out","w",stdout);
#define sspeed ios_base::sync_with_stdio(0);cin.tie(0)
#define maxn 31
const int inf=0x7fffffff;   //无限大
int visited[maxn][maxn][maxn];
struct node
{
    int x;
    int y;
    int z;
    int cnt;
};
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()
{
    int n,m,k;
    string s;
    while(cin>>n>>m>>k)
    {
        if(n==0&&m==0&&k==0)
            break;
        memset(visited,0,sizeof(visited));
        node sb;
        node sb2;
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
            {
                cin>>s;
                for(int t=0;t<k;t++)
                {
                    if(s[t]==‘S‘)
                    {
                        sb.x=i;
                        sb.y=j;
                        sb.z=t;
                        sb.cnt=0;
                    }
                    if(s[t]==‘E‘)
                    {
                        sb2.x=i;
                        sb2.y=j;
                        sb2.z=t;
                    }
                    if(s[t]==‘#‘)
                    {
                        visited[i][j][t]=1;
                    }
                }
            }
        }
    queue<node> q;
    q.push(sb);
    visited[sb.x][sb.y][sb.z]=1;
    int flag=0;
    while(!q.empty())
    {
        node now=q.front();
        for(int i=0;i<6;i++)
        {
            node next;
            next.x=now.x+dx[i];
            next.y=now.y+dy[i];
            next.z=now.z+dz[i];
            next.cnt=now.cnt+1;
            if(next.x<0||next.x>=n||next.y<0||next.y>=m||next.z<0||next.z>=k)
                continue;
            if(visited[next.x][next.y][next.z])
                continue;
            visited[next.x][next.y][next.z]=1;
            if(next.x==sb2.x&&next.y==sb2.y&&next.z==sb2.z)
                flag=next.cnt;
            if(flag>0)
                break;
            q.push(next);
        }
        if(flag>0)
            break;
        q.pop();
    }
    if(flag>0)
        printf("Escaped in %d minute(s).\n",flag);
    else
        cout<<"Trapped!"<<endl;

    }
    return 0;
}