hdu2825Wireless Password(ac+dp)

链接

状压dp+ac

dp[i+1][next[j]][st|tt]表示第i+1长度结点为next[j]状态为st|tt的时候的ans;

dp[i+1][next[j]][st|tt]+=dp[i][j][tt]; st记录当前结点是否为给定单词的结束点 

后一维用01状态表示截止到目前结点为止所包含的单词数量。

需要修改ac模板的一个地方，val[u]|=val[fail[u]];

#include <iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<stdlib.h>
#include<vector>
#include<cmath>
#include<queue>
#include<set>
using namespace std;
#define N 115
#define LL long long
#define INF 0xfffffff
const double eps = 1e-8;
const double pi = acos(-1.0);
const double inf = ~0u>>2;
const int child_num = 26;
const int mod = 20090717;
class AC
{
    private:
    int ch[N][child_num];
    int fail[N];
    int Q[N];
    int val[N];
    int sz;
    int id[128];
    int dp[30][N][1<<10];
    public:
    void init()
    {
        fail[0] =0;
        for(int i = 0 ;i < child_num ; i++)
        id[i+'a'] = i;
    }
    void reset()
    {
        memset(val,0,sizeof(val));
        memset(ch[0],0,sizeof(ch[0]));
        //memset(fail,0,sizeof(fail));
        sz = 1;
    }
    void insert(char *a,int key)
    {
        int p = 0;
        for(; *a ; a++)
        {
            int d = id[*a];
            if(ch[p][d]==0)
            {
                memset(ch[sz],0,sizeof(ch[sz]));
                ch[p][d] = sz++;
            }
            p = ch[p][d];
        }
        val[p] = (1<<key);
    }
    void construct()
    {
        int i,head=0,tail = 0;
        for(i = 0 ;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 = 0 ;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 k,int m)
    {
        int i,j,g,o;
        for(i = 0 ; i <= n ;i++)
            for(j = 0 ; j <= sz ; j++)
                for(g = 0 ;g  <=(1<<m) ; g++)
                dp[i][j][g] = 0;
        dp[0][0][0] = 1;
        for(i = 0; i < n ;i++)
            for(j = 0; j < sz ; j++)
            {
                for(int e =0 ; e < (1<<m) ; e++)
                {
                    if(!dp[i][j][e]) continue;
                    for(g = 0 ;g < child_num ; g++)
                    {
                        o = 0;
                        if(val[ch[j][g]])
                        {
                            o = val[ch[j][g]];
                        }
                        dp[i+1][ch[j][g]][e|o]=(dp[i+1][ch[j][g]][e|o]+dp[i][j][e])%mod;
                    }
                }
            }
        int ans = 0;
        for(i = 0 ; i < sz;i ++)
        {
            for(j = 0 ;j < (1<<m) ; j++)
            {
                if(!dp[n][i][j]) continue;
                int o =0 ;
                for(g = 0 ;g < m ; g++)
                if(j&(1<<g)) o++;
                if(o>=k)
                ans = (ans+dp[n][i][j])%mod;
            }
        }
        printf("%d
",ans);
    }
}ac;
char vir[15];
int main()
{
    int n,m,k,i;
    ac.init();
    while(scanf("%d%d%d",&n,&m,&k)!=EOF)
    {
        if(!n&&!m&&!k) break;
        ac.reset();
        for(i = 1; i <= m; i++)
        {
            scanf("%s",vir);
            ac.insert(vir,i-1);
        }
        ac.construct();
        ac.work(n,k,m);
    }
    return 0;
}