POJ 2251-Dungeon Master（BFS-三維迷宮）

You are trapped in a 3D dungeon and need to find the quickest way out! The dungeon is composed of unit cubes which may or may not be filled with rock. It takes one minute to move one unit north, south, east, west, up or down. You cannot move diagonally and the maze is surrounded by solid rock on all sides. 

Is an escape possible? If yes, how long will it take? 

The input consists of a number of dungeons. Each dungeon description starts with a line containing three integers L, R and C (all limited to 30 in size). 
L is the number of levels making up the dungeon. 
R and C are the number of rows and columns making up the plan of each level. 
Then there will follow L blocks of R lines each containing C characters. Each character describes one cell of the dungeon. A cell full of rock is indicated by a '#' and empty cells are represented by a '.'. Your starting position is indicated by 'S' and the exit by the letter 'E'. There's a single blank line after each level. Input is terminated by three zeroes for L, R and C.

Each maze generates one line of output. If it is possible to reach the exit, print a line of the form 

Escaped in x minute(s).

where x is replaced by the shortest time it takes to escape. 
If it is not possible to escape, print the line 

Trapped!

3 4 5
S....
.###.
.##..
###.#

#####
#####
##.##
##...

#####
#####
#.###
####E

1 3 3
S##
#E#
###

0 0 0

Escaped in 11 minute(s).
Trapped!

Ulm Local 1997

#include<iostream>
#include<cstdio>
#include<iomanip>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<map>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
#define INF 0x3f3f3f3f
#define MAXN 40
char ma[MAXN][MAXN][MAXN];//存迷宮地圖
int step[MAXN][MAXN][MAXN];//走的步數
bool vis[MAXN][MAXN][MAXN];//是否訪問過
int dir[6][3]= {0,0,1, 0,0,-1, 0,1,0, 0,-1,0, 1,0,0, -1,0,0}; //上下東西南北
bool flag;//能否走出迷宮
int d,r,c,ans;//深度、長度、寬度、總步數
struct Node
{
    int x,y,z;//深、長、寬
} s,e;//起始點和終點

void BFS()
{
    queue<Node> q;
    vis[s.z][s.x][s.y]=true;
    q.push(s);
    while(!q.empty())
    {
        Node pos=q.front(),temp;
        q.pop();
        for(int i=0; i<6; ++i)
        {
            temp.z=pos.z+dir[i][0];
            temp.x=pos.x+dir[i][1];
            temp.y=pos.y+dir[i][2];
            //是否訪問、是否能走、範圍是否在迷宮內
            if(!vis[temp.z][temp.x][temp.y]&&ma[temp.z][temp.x][temp.y]!='#'&&temp.x>=0&&temp.x<r&&temp.y>=0&&temp.y<c&&temp.z>=0&&temp.z<d)
            {
                if(temp.x==e.x&&temp.y==e.y&&temp.z==e.z)//到達終點
                {
                    ans=step[pos.z][pos.x][pos.y]+1;
                    flag=true;
                    return;
                }
                vis[temp.z][temp.x][temp.y]=true;//標記訪問
                step[temp.z][temp.x][temp.y]=step[pos.z][pos.x][pos.y]+1;//增加步數
                q.push(temp);
            }
        }
    }
}

int main()
{
#ifdef ONLINE_JUDGE
#else
    freopen("G:/cbx/read.txt","r",stdin);
    //freopen("F:/cb/out.txt","w",stdout);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0);
    while(cin>>d>>r>>c&&d&&r&&c)
    {
        flag=false;
        ans=0;
        memset(ma,'\0',sizeof(ma));
        memset(step,0,sizeof(step));
        memset(vis,false,sizeof(vis));
        for(int i=0; i<d; ++i)
            for(int j=0; j<r; ++j)
                for(int k=0; k<c; ++k)
                {
                    cin>>ma[i][j][k];
                    if(ma[i][j][k]=='S')//起點
                        s.z=i,s.x=j,s.y=k;
                    else if(ma[i][j][k]=='E')//終點
                        e.z=i,e.x=j,e.y=k;
                }
        BFS();
        if(flag) cout<<"Escaped in "<<ans<<" minute(s)."<<endl;
        else cout<<"Trapped!"<<endl;
    }
}