BFS POJ 2251 Dungeon Master

 

题目传送门

/*
    BFS：这题很有意思，像是地下城，图是立体的，可以从上张图到下一张图的对应位置，那么也就是三维搜索，多了z坐标轴
*/
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
using namespace std;

const int MAXN = 33;
const int INF = 0x3f3f3f3f;
struct Point    {
    int x, y, z, step;
};
char maze[MAXN][MAXN][MAXN];
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};
bool vis[MAXN][MAXN][MAXN];
int l, r, c;

bool judge(int x, int y, int z) {
    if (x < 1 || x > r || y < 1 || y > c || z < 1 || z > l || vis[z][x][y] || maze[z][x][y] == '#') return false;
    return true;
}

void BFS(void)  {
    int sx, sy, sz, ex, ey, ez;
    for (int i=1; i<=l; ++i)    {
        for (int j=1; j<=r; ++j)    {
            for (int k=1; k<=c; ++k)    {
                if (maze[i][j][k] == 'S')   {
                    sx = j; sy = k; sz = i;
                }
                else if (maze[i][j][k] == 'E')  {
                    ex = j; ey = k; ez = i;
                }
            }
        }
    }
    memset (vis, false, sizeof (vis));
    queue<Point> Q; Q.push ((Point) {sx, sy, sz, 0});
    bool flag = false;  vis[sz][sx][sy] = true;
    while (!Q.empty ()) {
        Point p = Q.front ();   Q.pop ();
        if (p.x == ex && p.y == ey && p.z == ez)  {
            printf ("Escaped in %d minute(s).\n", p.step);
            flag = true;    break;
        }
        for (int i=0; i<6; ++i) {
            int tx = p.x + dx[i];   int ty = p.y + dy[i];   int tz = p.z + dz[i];
            if (judge (tx, ty, tz)) {
                vis[tz][tx][ty] = true;
                Q.push (Point {tx, ty, tz, p.step + 1});
            }
        }
    }
    if (!flag)  puts ("Trapped!");
}

int main(void)  {       //POJ 2251 Dungeon Master
    while (scanf ("%d%d%d", &l, &r, &c) == 3)   {
        if (!l && !r && !c) break;
        for (int i=1; i<=l; ++i)    {
            for (int j=1; j<=r; ++j)    scanf ("%s", maze[i][j] + 1);
        }
        BFS ();
    }

    return 0;
}