BFS_poj 2251 Dungeon Master

/*
Sample Input

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

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

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

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

0 0 0

Sample Output

Escaped in 11 minute(s).
Trapped!
*/

#include<cstdio>
#include<queue>
#include<cstring>
#include<cstdlib>

using namespace std;

typedef struct point{
int x, y, z, r;
}point;

char str[31][31][31];

int arr[6][3] = {{0, 1, 0}, {0, -1, 0}, {1, 0, 0}, {-1, 0, 0},{0,0,1}, {0,0,-1}};

int bfs(point start, int l, int n, int m){
queue<point> que;
que.push(start);
point goal = {0,0,0,0}, p1 = {0,0,0,0};
while(!que.empty()){
p1 = que.front();
que.pop();
for(int k = 0; k < 6; k++){
goal.x = p1.x + arr[k][0];
goal.y = p1.y + arr[k][1];
goal.z = p1.z + arr[k][2];
goal.r = p1.r + 1;
if(str[goal.x][goal.y][goal.z] == 'E'){
return goal.r;
}
if(goal.x >= 0 && goal.x < l && goal.y >= 0 && goal.y < n && goal.z >= 0
&& goal.z < m && str[goal.x][goal.y][goal.z] != '#'){
str[goal.x][goal.y][goal.z] = '#';
que.push(goal);
}
}
}
return -1;
}
int main(){
int l, n, m, i, j;
while(scanf("%d%d%d", &l, &n, &m) && (l || m || n)){
getchar();
point start = {0,0,0,0};
int flag = 0;
for(int i = 0; i < l ; i++){
for(int j = 0; j < n; j++){
gets(str[i][j]);
if(!flag){
for(int k = 0; k < m; k++){
if(str[i][j][k] == 'S'){
start.x = i;
start.y = j;
start.z  = k;
start.r = 0;
flag = 1;
}
}
}
}
getchar();
}
int re = bfs(start, l, n, m);
if(re != -1) printf("Escaped in %d minute(s).\n", re);
else printf("Trapped!\n");
}
}