【搜索】 HDU 5025 Saving Tang Monk

优先队列+状压蛇+没有了

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <string>
#include <iostream>
#include <algorithm>
#include <sstream>
#include <math.h>
using namespace std;
#include <queue>
#include <stack>
#include <vector>
#include <deque>
#include <set>
#include <map>
#define cler(arr, val)    memset(arr, val, sizeof(arr))
#define IN     freopen ("in.txt" , "r" , stdin);
#define OUT  freopen ("out.txt" , "w" , stdout);
typedef long long  LL;
const int MAXN = 5040;//点数的最大值
const int MAXM = 20006;//边数的最大值
const int INF = 0x3f3f3f3f;
const int mod = 10000007;
char mp[102][102];
bool vis[102][102][30];
int n,t;
struct node
{
    int x,y,step;
    int key;
    int she;
    bool operator < (const node &a) const
    {
       return step>a.step;//最小值优先
    }
};
priority_queue<node>q;
int xx[4]= {1,0,-1,0};
int yy[4]= {0,1,0,-1};
int star[2],end[2];
bool judge(node p,int dd)
{
    if(p.she&(1<<dd))
        return false;
    return true;
}
int bfs(int x,int y)
{
    while(!q.empty())
        q.pop();
    memset(vis,false,sizeof(vis));
    node front,rear;
    front.x=x,front.y=y;
    front.key=0;
    front.step=0;
    front.she=0;
    vis[x][y][0]=true;
    q.push(front);
    while(!q.empty())
    {
        front=q.top();
        q.pop();
        for(int i=0; i<4; i++)
        {
            int dx=front.x+xx[i],dy=front.y+yy[i];
            if(dx>=0&&dy>=0&&dx<n&&dy<n&&mp[dx][dy]!='#'&&!vis[dx][dy][front.key])
            {
                if(t==front.key&&mp[dx][dy]=='T')//到终点
                {
                    return front.step+1;
                }
                else if(mp[dx][dy]==front.key+'0'+1)//拿到钥匙
                {
                    vis[dx][dy][front.key]=true;//标记
                    rear.key =front.key+1;
                    rear.x=dx,rear.y=dy,rear.step=front.step+1,rear.she=front.she;
                    q.push(rear);
                }
                else if(mp[dx][dy]>=0&&mp[dx][dy]<=5&&judge(front,mp[dx][dy]))//遇到蛇
                {
                    rear.x=dx,rear.y=dy,rear.key=front.key,rear.step=front.step+2,rear.she=(front.she|(1<<mp[dx][dy]));
                    vis[dx][dy][rear.key]=true;
                    q.push(rear);
                }
                else
                {
                    rear.x=dx,rear.y=dy,rear.key=front.key,rear.step=front.step+1,rear.she=front.she;
                    vis[dx][dy][rear.key]=true;
                    q.push(rear);
                }
            }
        }
    }
    return -1;
}
int main()
{
    //IN;
    while(scanf("%d%d",&n,&t),n+t)
    {
        for(int i=0; i<n; i++)
            scanf("%s",mp[i]);
        int ss=0;
        for(int i=0; i<n; i++)
        {
            for(int j=0; j<n; j++)
            {
                if(mp[i][j]=='K')
                    star[0]=i,star[1]=j;
                else if(mp[i][j]=='T')
                    end[0]=i,end[1]=j;
                else if(mp[i][j]=='S')
                    mp[i][j]=ss++;
            }
        }
        int ans=bfs(star[0],star[1]);
        if(ans==-1)
            printf("impossible\n");
        else printf("%d\n",ans);
    }
    return 0;
}