推箱子游戏

推箱子

/**************************************************************
  作者：陈新
  邮箱：cx2pirate@gmail.com
  用途：hdu1254_2
  时间ﺿ014.3.31 21:11
  测试ﺿ0447364    2014-04-01 08:51:18    Accepted    1254    15MS    296K    3724 B    G++    超级旅行者 
  *************************************************************/ 

#include <cstdio>
#include <memory.h>
#include <queue>
#include <map>

using namespace std;

#define MAPSIZE 7
#define FLOOR 0
#define WALL 1
#define BOX 2
#define DESTINATION 3
#define WORKER 4

//坐标
typedef struct COOR{
    int x,y;
    bool operator ==(const COOR &rhs) const{
        return x == rhs.x && y == rhs.y;
    }
    bool operator !=(const COOR &rhs) const{
        return x != rhs.x || y != rhs.y;
    }
    bool operator <(const COOR &rhs) const{
        return x < rhs.x || (x == rhs.x && y < rhs.y);
    }
}COOR;

//worker,box的位置组成搜索节点
//为使用map 对运算法重载
typedef struct NODE{
    COOR worker;
    COOR box;
    int dir;
    int steps;
    bool operator <(const NODE &rhs)const{
        return worker < rhs.worker || (worker == rhs.worker && box < rhs.box);
    }
}NODE;


int gMap[MAPSIZE][MAPSIZE];                    //地图
int vis[MAPSIZE][MAPSIZE];                    //dfs中使用，
int mapX,mapY;                                //mapX地图高，mapY地图宽
bool found;
int DIREC[4][2] = {{-1,0},{1,0},{0,-1},{0,1}};
int REVER[4] = {1,0,3,2};                    //DIREC中反方向对应的索引
queue<NODE> unvis;                            
map<NODE,bool> visited;                        //用map记录已经扩展的节点，

void initMap();                                        //初始化地图
int findAWay();                                        //找到推箱子路径，有路径返回最小步骤，否则返回-1
void getCoor(COOR *worker,COOR *box,COOR *dest);    //从地图中获得worker,box,destination初始坐标
COOR move(COOR from,int dir);                                            //移动一个坐标，返回移动后的坐标
void addNodes(COOR worker,COOR box,int steps);        //把worker移动到box上下左右组成搜索节点，添加到unvis
bool reach(COOR worker,COOR box,COOR aroundBox);    //返回worker是否能到达box周围的坐标aroundBox
void dfs(COOR worker,COOR box,COOR aroundBox);        //reach中采用的dfs
bool notWall(COOR pos);                                //坐标在地图内且不是墙返回真，否则返回假

int main(){
    int caseNum;
    scanf("%d",&caseNum);

    while(caseNum--){
        initMap();
        int steps = findAWay();
        printf("%d\n",steps);
    }
}

void initMap(){
    scanf("%d%d",&mapX,&mapY);
    for(int i = 0;i < mapX;i++){
        for(int j = 0;j < mapY;j++){
            scanf("%d",&gMap[i][j]);
        }
    }
}

int findAWay(){
    COOR worker,box,dest;
    getCoor(&worker,&box,&dest);
    visited.clear();
    while(!unvis.empty()){
        unvis.pop();
    }
    addNodes(worker,box,0);
    while(!unvis.empty()){
        NODE cur = unvis.front();
        unvis.pop();
        if(cur.box == dest){
            return cur.steps;
        }
//        printf("worker : %d %d\tbox : %d %d\tsteps : %d\n",cur.worker.x,cur.worker.y,cur.box.x,cur.box.y,cur.steps);
        COOR bNext = move(cur.box,cur.dir);
        if(notWall(bNext)){
            addNodes(cur.worker,bNext,cur.steps + 1);
        }
    }
    return -1;
}

void addNodes(COOR worker,COOR box,int steps){
    for(int dir = 0;dir < 4;dir++){
        COOR aroundBox = move(box,dir);
        if(reach(worker,box,aroundBox)){
            NODE node;
            node.worker = aroundBox;
            node.box = box;
            node.steps = steps;
            node.dir = REVER[dir];
            if(!visited[node]){
                visited[node] = true;
                unvis.push(node);
            }
        }
    }
}

COOR move(COOR from,int dir){
    COOR dest = from;
    dest.x += DIREC[dir][0];
    dest.y += DIREC[dir][1];
    return dest;
}

bool reach(COOR worker,COOR box,COOR aroundBox){
    memset(vis,false,sizeof(vis));
    found = false;
    dfs(worker,box,aroundBox);
    return found;
}

void dfs(COOR worker,COOR box,COOR aroundBox){
    if(worker == aroundBox){
        found = true;
    }
    if(found){
        return;
    }

    for(int dir = 0;dir < 4;dir++){
        COOR wNext = move(worker,dir);
        if(notWall(wNext) && wNext != box && !vis[wNext.x][wNext.y]){
            vis[wNext.x][wNext.y] = true;
            dfs(wNext,box,aroundBox);
        }
    }
}

bool notWall(COOR pos){
    return pos.x >= 0 && pos.x < mapX && pos.y >= 0 && pos.y < mapY && gMap[pos.x][pos.y] != WALL;
}

void getCoor(COOR *worker,COOR *box,COOR *dest){
    for(int i = 0;i < mapX;i++){
        for(int j = 0;j < mapY;j++){
            if(gMap[i][j] == WORKER){
                worker ->x = i;
                worker ->y = j;
            }
            else if(gMap[i][j] == BOX){
                box ->x = i;
                box ->y = j;
            }
            else if(gMap[i][j] == DESTINATION){
                dest ->x = i;
                dest ->y = j;
            }
        }
    }
}