POJ 2251 Dungeon Master （简单三维广搜）

最新推荐文章于 2019-04-15 17:11:53 发布

H_usky

最新推荐文章于 2019-04-15 17:11:53 发布

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Dungeon Master

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 5
S....
.###.
.##..
###.#

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

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

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

0 0 0

Sample Output

Escaped in 11 minute(s).
Trapped!

解题思路：

合理利用结构体、队列、标记将每一个步骤、每一种情况思考全面

#include<cstdio>
#include<queue>
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
const int inf = 0x3f3f3f3f;
const int maxx = 35;
char mapp[maxx][maxx][maxx];
int l,m,n,step[maxx][maxx][maxx],ez,ex,ey;
int book[maxx][maxx][maxx];
int nex[6][3]={0,1,0,  0,0,1,  1,0,0,  0,-1,0,  0,0,-1,  -1,0,0,};   //枚举每种移动
struct node
{
    int x,y,z;
}s,t,now; 
void bfs();
int main()
{
    int i,j,k;
    while(scanf("%d%d%d",&l,&m,&n),l+m+n){
        for(i=0;i<l;i++){
            for(j=0;j<m;j++){
                for(k=0;k<n;k++){
                    scanf(" %c",&mapp[i][j][k]);
                    if(mapp[i][j][k]=='S'){
                        s.z=i;
                        s.x=j;
                        s.y=k;
                    }
                    else if(mapp[i][j][k]=='E'){
                        ez=i;
                        ex=j;
                        ey=k;
                    }
                }
            }
        }
        memset(step,0x3f,sizeof(step));                //初始化
        memset(book,0,sizeof(book));
        step[s.z][s.x][s.y]=0;
        book[s.z][s.x][s.y]=1;
        bfs();
        if(step[ez][ex][ey]==inf)  printf("Trapped!\n");
        else     printf("Escaped in %d minute(s).\n",step[ez][ex][ey]);
    }
    return 0;
}
void bfs()
{
    queue<node>q;
    q.push(s);
    while(!q.empty()){
        t=q.front();
        if(t.z==ez&&t.x==ex&&t.y==ey)  return ;        // 如果到达终点 返回
        q.pop();                                       //入队
        for(int i=0;i<6;i++){
            now.z=t.z+nex[i][0];
            now.x=t.x+nex[i][1];
            now.y=t.y+nex[i][2];
            if(now.z<0||now.z>=l||now.x<0||now.x>=m||now.y<0||now.y>=n)  continue;//判断当前的值是否出地图
            if(mapp[now.z][now.x][now.y]=='#') continue;                          //判断当前位置是否是墙
            if(book[now.z][now.x][now.y]==1)   continue;                          //判断当前是否被标记
            step[now.z][now.x][now.y]=step[t.z][t.x][t.y]+1;
            book[now.z][now.x][now.y]=1;                                          //标记
            q.push(now);                                                          //入队
        }
    }
}