POJ 2251 Dungeon Master (BFS)

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**链接 : ** Here!

**思路 : ** 三维的搜索, 只需要注意输入的图$G$, 第一为是 $z$ 即可. 剩下的就是普通的搜索, 只不过多加了一维而已...

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/*************************************************************************
	> File Name: E.cpp
	> Author: 
	> Mail: 
	> Created Time: 2017年11月26日 星期日 10时51分05秒
 ************************************************************************/

#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <queue>
using namespace std;

#define MAX_N 40
int L, R, C;
int dx[6] = {0, 0, -1, 1, 0, 0};
int dy[6] = {-1, 1, 0, 0, 0, 0};
int dz[6] = {0, 0, 0, 0, 1, -1};
int vis[MAX_N][MAX_N][MAX_N];
char G[MAX_N][MAX_N][MAX_N];

struct Point {
    Point() {}
    Point(int x, int y, int z, int step) : x(x), y(y), z(z), step(step) {}
    int x, y, z;
    int step;
};
Point st, ed;

void read() {
    for (int k = 0 ; k < L ; ++k) {
        getchar();
        for (int i = 0 ; i < R ; ++i) {
            scanf("%s", G[k][i]);
        }
    }
    for (int k = 0 ; k < L ; ++k) {
        for (int i = 0 ; i < R ; ++i) {
            for (int j = 0 ; j < C ; ++j) {
                if (G[k][i][j] == 'S') {
                    st.z = k; st.x = i; st.y = j;
                    st.step = 0;
                }
                if (G[k][i][j] == 'E') {
                    ed.z = k; ed.x = i; ed.y = j;
                    ed.step = 0;
                }
            }
        }
    }
}

int check(Point pt) {
    if (pt.x < 0 || pt.x >= R || pt.y < 0 || pt.y >= C || pt.z < 0 || pt.z >= L) return 0;
    if (vis[pt.x][pt.y][pt.z]) return 0;
    if (G[pt.z][pt.x][pt.y] == '#') return 0;
    return 1;
}

int BFS() {
    queue<Point> que;
    vis[st.x][st.y][st.z] = 1;
    que.push(st);
    while (!que.empty()) {
        Point now = que.front();
        que.pop();
        if (now.x == ed.x && now.y == ed.y && now.z == ed.z) {
            return now.step;
        }
        for (int i = 0 ; i < 6 ; ++i) {
            Point temp(now.x + dx[i], 
                       now.y + dy[i], 
                       now.z + dz[i],
                       now.step + 1);
            if (!check(temp)) continue;
            vis[temp.x][temp.y][temp.z] = 1;
            que.push(temp);
        }
    }
    return -1;
}
void solve() {
    int ret = BFS();
    if (ret != -1) {
        printf("Escaped in %d minute(s).
", ret);
    } else {
        printf("Trapped!
");
    }
}
int main() {
    // freopen("./in.in", "r", stdin);
    while (scanf("%d%d%d", &L, &R, &C) != EOF) {
        if (L == 0 && R == 0 && C == 0) break;
        memset(vis, 0, sizeof(vis));
        memset(G, 0, sizeof(G));
        read();
        solve();
    }
    return 0;
}