hdu4511小明系列故事——女友的考验(ac自动机+最短路）

链接

预处理出来任意两点的距离，然后可以顺着trie树中的节点走，不能走到不合法的地方，另开一维表示走到了哪里，依次来更新。

注意判断一下起点是不是合法。

#include <iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<stdlib.h>
#include<vector>
#include<cmath>
#include<queue>
#include<set>
using namespace std;
#define N 510
#define LL long long
const double eps = 1e-8;
const double pi = acos(-1.0);
const double INF = 1e21;
const int child_num = 51;
double w[55][55];
class AC
{
    private:
    int ch[N][child_num];
    int fail[N];
    int val[N];
    int id[128];
    int Q[N];
    double dis[55][N];
    int sz;
    public:
    void init()
    {
        fail[0] = 0;
        for(int i = 0 ; i< child_num ; i++)
        id[i] = i;
    }
    void reset()
    {
        memset(ch[0],0,sizeof(ch[0]));
        memset(val,0,sizeof(val));
        sz = 1;
    }
    void insert(int *a,int k,int key)
    {
        int i,p=0;
        for(i = 1;i <= k; i++)
        {
            int d = a[i];
            if(ch[p][d]==0)
            {
                memset(ch[sz],0,sizeof(ch[sz]));
                ch[p][d]= sz++;
            }
            p = ch[p][d];
        }
        val[p] = key;
    }
    void construct()
    {
        int i,head= 0 ,tail = 0;
        for(i = 1 ;i < child_num ; i++)
        {
            if(ch[0][i])
            {
                fail[ch[0][i]] = 0;
                Q[tail++] = ch[0][i];
            }
        }
        while(head!=tail)
        {
            int u = Q[head++];
            val[u]|=val[fail[u]];
            for(i = 1; i < child_num ; i++)
            {
                if(ch[u][i])
                {
                    fail[ch[u][i]] = ch[fail[u]][i];
                    Q[tail++] = ch[u][i];
                }
                else ch[u][i] = ch[fail[u]][i];
            }
        }
    }
    void work(int n)
    {
        int i,j,g;
        for(i = 1; i <= n ;i++)
        for(j = 0 ; j <= sz ;j++)
        dis[i][j] = INF;
        if(val[1])
        {
            puts("Can not be reached!");
            return ;
        }
        dis[1][ch[0][1]] = 0;
        for(i = 1 ; i <= n ;i++)
        {
            for(j = 0; j < sz ;j++)
            {
                for(g = 1; g <= n ;g++)
                {
                    int np = ch[j][g];
                    if(val[np]) continue;
                    dis[g][np] = min(dis[g][np],dis[i][j]+w[i][g]);
                }
            }
        }
        double ans = INF;
        for(i = 0 ; i < sz ; i++)
        {
            ans = min(ans,dis[n][i]);
        }
        if(fabs(ans-INF)<eps) puts("Can not be reached!");
        else
        printf("%.2f
",ans);
    }
}ac;
struct node
{
    double x,y;
}pp[55];
double cdis(node a,node b)
{
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
int a[10];
int main()
{
    int n,m,k,i,j;
    ac.init();
    while(scanf("%d%d",&n,&m)&&n&&m)
    {
        ac.reset();
        for(i = 1 ;i <= n; i++)
        {
            scanf("%lf%lf",&pp[i].x,&pp[i].y);
        }
        for(i = 1; i <= n ;i++)
            for(j = 1; j <= n ;j++)
            w[i][j] = cdis(pp[i],pp[j]);
        for(i = 1; i <= m ; i++)
        {
            scanf("%d",&k);
            for(j= 1 ;j <= k; j++)
            scanf("%d",&a[j]);
            ac.insert(a,k,1);
        }
        ac.construct();
        ac.work(n);
    }
    return 0;
}