ZOJ 3531 模拟＋BFS

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <queue>
#include <set>
#include <stack>
#include <bitset>

using namespace std;

#define print(x) cout<<x<<endl
#define input(x) cin>>x
#define SIZE 12
#define elif else if
#define INF 1<<30
#define MOD 100000007

struct point
{
    int x,y;
    point(){x=y=-1;}
    point(int i_x,int i_y)
    {
        x=i_x;y=i_y;
    }
    friend bool operator == (const point& a,const point& b)
    {
        return a.x==b.x && a.y==b.y;
    }
    
    friend bool operator != (const point& a,const point& b)
    {
        return !(a.x==b.x && a.y==b.y);
    }
};

char g[SIZE][SIZE];
point piece[SIZE];
int m,n,ind;
const int mx[]={0,1,0,-1};
const int my[]={-1,0,1,0};
bitset<MOD> hash;
//TLE:
//Hash is faster than Set


int makeStatus(const point& pawn,const point& mir,const point& knight,int knightDir,int getMem)
{
    int res=0;
    res|=getMem;
    res<<=4;res|=knight.x;
    res<<=4;res|=knight.y;
    res<<=2;res|=knightDir;
    res<<=4;res|=mir.x;
    res<<=4;res|=mir.y;
    res<<=4;res|=pawn.x;
    res<<=4;res|=pawn.y;
    return res;
}

bool inMap(const point& p)
{
    if(p.x>=0 && p.x<m && p.y>=0 && p.y<n)
    {
        if(g[p.y][p.x]=='R') return false;
        else return true;
    }
    return false;
}

struct node
{
    unsigned int status;
    int step;

    node(){}
    node(int i_status,int i_step)
    {
        status=i_status;
        step=i_step;
    }
    int OK()//Drei Status caused WA
    {
        int st=status;
        int res=status>>26;
        int a,b;
        a=b=(1<<4)-1;
        b&=st;st>>=4;
        a&=st;st>>=4;
        point pawn=point(a,b);
        a=b=(1<<4)-1;
        b&=st;st>>=4;
        a&=st;st>>=4;
        point mirPawn=point(a,b);
        int ok=(1<<ind)-1;
        if(ind==0) ok=0;
        if(g[pawn.y][pawn.x]=='E' && g[mirPawn.y][mirPawn.x]=='E')
        {
            if(res==ok) return true;
            else return -1;
        }
        else return false;
    }
    bool move(int dir)
    {
        step++;
        int a,b;
        a=b=(1<<4)-1;
        b&=status;status>>=4;
        a&=status;status>>=4;
        point pawn=point(a,b);
        
        a=b=(1<<4)-1;
        b&=status;status>>=4;
        a&=status;status>>=4;
        point mirPawn=point(a,b);

        a=(1<<2)-1;
        a&=status;
        int knightDir=a;
        status>>=2;

        a=b=(1<<4)-1;
        b&=status;status>>=4;
        a&=status;status>>=4;
        point knight=point(a,b);

        int gain=status;

        point nextPawn=pawn;
        nextPawn.x+=mx[dir];
        nextPawn.y+=my[dir];
        if(inMap(nextPawn))
        {
            if(nextPawn==knight || nextPawn==mirPawn) return false;
            pawn=nextPawn;
        }
        else return false;

        point nextMirPawn=mirPawn;
        nextMirPawn.x+=mx[(dir+2)%4];
        nextMirPawn.y+=my[(dir+2)%4];
        if(inMap(nextMirPawn) && nextMirPawn!=knight && nextMirPawn!=pawn)
        {
            mirPawn=nextMirPawn;
        }
        point nextKnight=knight;
        nextKnight.x+=mx[knightDir];
        nextKnight.y+=my[knightDir];
        if(inMap(nextKnight)) knight=nextKnight;
        else knightDir=(knightDir+2)%4;

        if(g[pawn.y][pawn.x]=='E' && g[mirPawn.y][mirPawn.x]=='E')
        {
            status=makeStatus(pawn,mirPawn,knight,knightDir,gain);
        }
        else
        {
            if(knight==pawn || knight==mirPawn) return false;
            for(int i=0;i<ind;i++)
            {
                if(pawn==piece[i]) gain|=(1<<i);//Only Alice can attach to the Memory Piece WA
            }
            status=makeStatus(pawn,mirPawn,knight,knightDir,gain);
        }
        return true;
    }
    
    void printinfo()
    {
        char tg[SIZE][SIZE];
        memcpy(tg,g,sizeof(g));
        print("INFO:"<<step);
        int st=status;
        int a,b;
        a=b=(1<<4)-1;
        b&=status;status>>=4;
        a&=status;status>>=4;
        point pawn=point(a,b);
        tg[b][a]='A';
        
        a=b=(1<<4)-1;
        b&=status;status>>=4;
        a&=status;status>>=4;
        point mirPawn=point(a,b);
        tg[b][a]='B';

        a=(1<<2)-1;
        a&=status;
        int knightDir=a;
        status>>=2;
        printf("KnightDir:%d\n",knightDir);

        a=b=(1<<4)-1;
        b&=status;status>>=4;
        a&=status;status>>=4;
        point knight=point(a,b);
        tg[b][a]='K';
        int gain=status;
        printf("Gain:%d\n",gain);
        status=st;
        for(int i=0;i<ind;i++)
        {

            if(!(gain & (1<<i)))
            {
                tg[piece[i].y][piece[i].x]='M';
            }
        }
        for(int i=0;i<n;i++) print(tg[i]);
        print("-------------------");
    }
};


inline int char2Dir(char x)
{
    switch(x)
    {
        case 'N':return 0;break;
        case 'E':return 1;break;
        case 'S':return 2;break;
        case 'W':return 3;break;
    }
    return -1;
}


int bfs(int i_status)
{
    queue<node> q;
    int ans=INF;
    hash.reset();
    q.push(node(i_status,0));
    while(!q.empty())
    {
        node now=q.front();
        q.pop();
        //now.printinfo();
        if(hash[now.status%MOD]) continue;
        else hash[now.status%MOD]=1;
        int ok=now.OK();
        if(ok==1)
        {
            ans=min(ans,now.step);
            break;
        }
        elif(ok==-1) continue;
        for(int i=0;i<4;i++)
        {
            node next=now;
            if(next.move(i)) q.push(next);
        }
    }
    return ans;
}

int main()
{
    //freopen("input.txt","r",stdin);
    char cmd[4];
    while(input(n>>m))
    {
        for(int i=0;i<n;i++) scanf("%s",g[i]);

        scanf("%s",cmd);
        ind=0;
        point pawn,mirPawn;
        point knight;
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
            {
                if(g[i][j]=='A') pawn=point(j,i);
                elif(g[i][j]=='B') mirPawn=point(j,i);
                elif(g[i][j]=='K') knight=point(j,i);
                elif(g[i][j]=='M') piece[ind++]=point(j,i);

                if(g[i][j]!='E' && g[i][j]!='*' && g[i][j]!='R')
                {
                    g[i][j]='*';
                }
            }
        }
        int status=makeStatus(pawn,mirPawn,knight,char2Dir(*cmd),0);
        int ans=bfs(status);
        if(ans>=INF) ans=-1;
        print(ans);
    }
    return 0;
}