hdu 1732 推箱子 三个箱子

#include <iostream>
#include <queue>
using namespace std;

struct Point
{
    int x, y;
};

struct Node
{
    Point you, box[3];
    int step;
};

int n, m;
char map[8][8];
Node first, next;
bool hash[8][8][8][8][8][8][8][8];
int dir[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};

void setHash(Node a)
{
    hash[a.you.x][a.you.y][a.box[0].x][a.box[0].y][a.box[1].x][a.box[1].y][a.box[2].x][a.box[2].y] = true;
}

bool getHash(Node a)
{
    return hash[a.you.x][a.you.y][a.box[0].x][a.box[0].y][a.box[1].x][a.box[1].y][a.box[2].x][a.box[2].y];
}

bool checkPoint(Point a)
{
    if (a.x >= 0 && a.x < n && a.y >= 0 && a.y < m && map[a.x][a.y] != '#')
    {
        return true;
    }
    return false;
}

//下一步是否是箱子
int isBox(Point a)
{
    for (int i = 0; i < 3; ++i)
    {
        if (first.box[i].x == a.x && first.box[i].y == a.y)
        {
            return i;
        }
    }
    return -1;
}

//箱子是否可推
bool isCanMove(Point a, int b, int di)
{
    Point c;
    c.x = a.x + dir[di][0];
    c.y = a.y + dir[di][1];
   
    if (!checkPoint(c))
    {
        return false;
    }
   
    for (int i = 0; i < 3; ++i)
    {
        if (i == b)
        {
            continue;
        }
        else if (first.box[i].x == c.x && first.box[i].y == c.y)
        {
            return false;
        }
    }
    return true;
}

//判断是否结束
bool isEnd(Node a)
{
    if (map[a.box[0].x][a.box[0].y] == '@' &&
        map[a.box[1].x][a.box[1].y] == '@' &&
        map[a.box[2].x][a.box[2].y] == '@')
    {
        return true;
    }
    return false;
}

//输入及初始化
void init()
{
    memset(hash, 0, sizeof(hash));
    int i, j, k = 0;
    for (i = 0; i < n; ++i)
    {
        getchar();
        for (j = 0; j < m; ++j)
        {
            scanf("%c", &map[i][j]);
            if (map[i][j] == 'X')
            {
                first.you.x = i;
                first.you.y = j;
            }
            else if (map[i][j] == '*')
            {
                first.box[k].x = i;
                first.box[k++].y = j;
            }
        }
    }
    first.step = 0;
    setHash(first);
}

int bfs()
{
    queue <Node> Q;
    Q.push(first);

    while (!Q.empty())
    {
        first = Q.front();
        Q.pop();
        if (isEnd(first))
        {
            return first.step;
        }
        for (int i = 0; i < 4; ++i)
        {
            next = first;
            next.you.x = first.you.x + dir[i][0];
            next.you.y = first.you.y + dir[i][1];
            next.step = first.step + 1;
            if (checkPoint(next.you))
            {
                int k = isBox(next.you);
                if (k != -1)
                {
                    if (isCanMove(next.you, k, i))
                    {
                        next.box[k].x += dir[i][0];
                        next.box[k].y += dir[i][1];
                        if (!getHash(next))
                        {
                            setHash(next);
                            Q.push(next);
                        }
                    }
                }
                else
                {
                    if (!getHash(next))
                    {
                        setHash(next);
                        Q.push(next);
                    }
                }
            }
        }
    }
    return -1;
}

int main()
{
    while (scanf("%d %d", &n, &m) != EOF)
    {
        init();
        printf("%d\n", bfs());
    }
    return 0;
}