HDU_5094_dfs

Posted 2020-08-09 冷暖知不知

http://acm.hdu.edu.cn/showproblem.php?pid=5094

 

bfs,vis[x][y][z]，z表示钥匙的状态，用二进制来表示，key[x][y]储存当前位置钥匙的二进制表示。

注意起始点有钥匙的情况。

 

#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;

struct point
{
    int x,y,counts,mykey;
}start;

int n,m,p,k,s,flag,door[55][55][55][55],key[55][55],vis[55][55][2048],dir[4][2] = {-1,0,0,-1,1,0,0,1};

int main()
{
    while(~scanf("%d%d%d",&n,&m,&p))
    {
        memset(door,-1,sizeof(door));
        memset(key,0,sizeof(key));
        memset(vis,0,sizeof(vis));
        scanf("%d",&k);
        int x1,y1,x2,y2,type;
        while(k--)
        {
            scanf("%d%d%d%d%d",&x1,&y1,&x2,&y2,&type);
            door[x1][y1][x2][y2] = type;
            door[x2][y2][x1][y1] = type;
        }
        scanf("%d",&s);
        int x,y,keytype;
        while(s--)
        {
            scanf("%d%d%d",&x,&y,&keytype);
            key[x][y] |= 1<<(keytype-1);
        }
        queue<point> q;
        start.x = 1;
        start.y = 1;
        start.counts = 0;
        start.mykey = key[1][1];
        vis[1][1][start.mykey] = 1;
        q.push(start);
        flag = 1;
        while(!q.empty())
        {

            point now = q.front();
            q.pop();
            if(now.x == n && now.y == m)
            {
                flag = 0;
                printf("%d\n",now.counts);
                break;
            }
            for(int i = 0;i < 4;i++)
            {
                point temp;
                temp.x = now.x+dir[i][0];
                temp.y = now.y+dir[i][1];
                if(temp.x < 1 || temp.x > n || temp.y < 1 || temp.y > m)    continue;
                if(door[now.x][now.y][temp.x][temp.y] != -1 &&(now.mykey & 1<<(door[now.x][now.y][temp.x][temp.y]-1)) == 0)  continue;
                temp.counts = now.counts+1;
                temp.mykey = now.mykey | key[temp.x][temp.y];
                if(vis[temp.x][temp.y][temp.mykey]) continue;
                vis[temp.x][temp.y][temp.mykey] = 1;
                q.push(temp);
            }
        }
        if(flag)    printf("-1\n");
    }
}