HDU_1253 胜利大逃亡(BFS)

　　纠结一晚上，注意细节啊！！！（看到有很多解题报告都用<queue>，我不太喜欢用STL的东西。。。）

My Code:

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

const int N = 51;

struct node
{
    int x;
    int y;
    int z;
    int t;
}q[N*N*N];

int d[6][3] = {{1, 0, 0}, {-1, 0, 0}, {0, 1, 0}, {0, -1, 0}, {0, 0, -1}, {0, 0, 1}};
int map[N][N][N];
int ans, T, X, Y, Z;

int bfs()
{
    int f = 0, r = 0, i;
    node p;
    map[0][0][0] = 1;
    q[0].x = 0; q[0].y = 0;
    q[0].z = 0; q[0].t = 0;
    while(f <= r)
    {
        p = q[f++];

        for(i = 0; i < 6; i++)
        {
            int a = p.x + d[i][0];
            int b = p.y + d[i][1];
            int c = p.z + d[i][2];
            if(a >= 0 && a < X && b >= 0 && b < Y && c >= 0 && c < Z && !map[a][b][c])
            {
                if(a == X-1 && b == Y-1 && c == Z-1 && p.t+1 <= T)
                {
                    ans = p.t + 1;
                    return 1;
                }r++;
                map[a][b][c] = 1;
                q[r].x = a;
                q[r].y = b;
                q[r].z = c;
                q[r].t = p.t+1;
            }
        }
    }
    return 0;
}

int main()
{
    //freopen("data.in", "r", stdin);
    int t, i, j, k;
    scanf("%d", &t);
    while(t--)
    {
        scanf("%d%d%d%d", &X, &Y, &Z, &T);

        memset(map, 0, sizeof(map));

        for(i = 0; i < X; i++)
            for(j = 0; j < Y; j++)
                for(k = 0; k < Z; k++)
                    scanf("%d", &map[i][j][k]);
        ans = 0;
        if(bfs())
            printf("%d\n", ans);
        else
            printf("-1\n");
    }
    return 0;
}