poj 2251 Dungeon Master

Dungeon Master

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 36311 Accepted: 13837

Description

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? 

Input

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.

Output

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!

Sample Input

3 4 5S.....###..##..###.#############.####...###########.#######E1 3 3S###E####0 0 0

Sample Output

Escaped in 11 minute(s).Trapped!

题目大意：

这个题目是一个三维的空间图形，#不能通行，.可以通行，每走一步花费一分钟的时间，问从S到E最短需要多长时间，不能到达

输出
Trapped!
题目解析：
这是一个简单的BFS题
代码：
#include<cstdio>#include<iostream>#include<cstring>#include<algorithm>#include<queue>using namespace std;const int maxn=35;char node[maxn][maxn][maxn];int vis[maxn][maxn][maxn];int dir[6][3]={{0,0,1},{0,0,-1},{1,0,0},{-1,0,0},{0,1,0},{0,-1,0}};int x,y,z;int ex,ey,ez,ok;struct trip{    int x;    int y;    int z;    int step;};int check(int p,int r,int s){    if(p<0||p>=x||r<0||r>=y||s<0||s>=z||node[p][r][s]=='#')        return 1;    return vis[p][r][s];}void BFS(int p,int r,int s){    trip a,next;    queue<trip>q;    a.x=p;    a.y=r;    a.z=s;    a.step=0;    q.push(a);    while(!q.empty())    {      a=q.front();      q.pop();      if(a.x==ex&&a.y==ey&&a.z==ez)         {             cout<<"Escaped in "<<a.step<<" minute(s)."<<endl;             ok=1;             break;         }            for(int i=0;i<6;i++)            {                next.x=a.x+dir[i][0];                next.y=a.y+dir[i][1];                next.z=a.z+dir[i][2];                if(check(next.x,next.y,next.z))                    continue;                    next.step=a.step+1;                   vis[next.x][next.y][next.z]=1;                   q.push(next);            }    }}int main(){    //freopen("in.txt","r",stdin);    while(cin>>x>>y>>z&&x&&y&&z)    {        ok=0;        memset(node,0,sizeof(node));        memset(vis,0,sizeof(vis));     for(int i=0;i<x;i++)            for(int j=0;j<y;j++)            cin>>node[i][j];    for(int i=0;i<x;i++)        for(int j=0;j<y;j++)            for(int k=0;k<z;k++)             if(node[i][j][k]=='E')             {                 ex=i;                 ey=j;                 ez=k;                 break;             }    for(int i=0;i<x;i++)        for(int j=0;j<y;j++)            for(int k=0;k<z;k++)                if(node[i][j][k]=='S') BFS(i,j,k);                if(!ok) cout<<"Trapped!"<<endl;    }    return 0;}