hdu 2825 Wireless Password 【ac自动机+dp】

我的第一道ac自动机+dp

学了那么久ac自动机，直到现在才会把它和dp结合在一起

结合在一起也没以前感觉的那么神奇，实际上就是图论中的记忆化搜索，ac自动机是一个图，在这个图上进行dp过程就叫记忆化搜索，和树形dp也挺像的~

#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<queue>
#include<stack>
#include<string>
#include<map>
#include<set>
#include<cmath>
#include<cassert>
#include<cstring>
#include<iomanip>
using namespace std;

#ifdef _WIN32
#define i64 __int64
#define out64 "%I64d\n"
#define in64 "%I64d"
#else
#define i64 long long
#define out64 "%lld\n"
#define in64 "%lld"
#endif

#define FOR(i,a,b)      for( int i = (a) ; i <= (b) ; i ++)
#define FF(i,a)         for( int i = 0 ; i < (a) ; i ++)
#define FFD(i,a)        for( int i = (a)-1 ; i >= 0 ; i --)
#define S64(a)          scanf(in64,&a)
#define SS(a)           scanf("%d",&a)
#define LL(a)           ((a)<<1)
#define RR(a)           (((a)<<1)+1)
#define pb              push_back
#define CL(Q)           while(!Q.empty())Q.pop()
#define MM(name,what)   memset(name,what,sizeof(name))
#define read            freopen("in.txt","r",stdin)
#define write           freopen("out.txt","w",stdout)

const int inf = 0x3f3f3f3f;
const i64 inf64 = 0x3f3f3f3f3f3f3f3fLL;
const double oo = 10e9;
const double eps = 1e-10;
const double pi = acos(-1.0);
const int mod = 20090717;
const int maxn = 121;
const int maxc = 26;
const int hashsize = 1<<10;
const int head = 0;

struct zz
{
    short to[26];
    short fail;
    short id;
}zx[maxn];

struct aa
{
    int len;
    int pos;
    int s;
}as;

int n,m,k,use;
string s;
int dp[maxc][maxn][hashsize+1]; // len | now | state
bool ok[maxn];
int fs[maxn];
bool hash[maxc][maxn][hashsize+1];
char ss[12];


inline int get()
{
    use++;
    zx[use].fail = 0;
    zx[use].id = -1;
    MM(zx[use].to,-1);
    return use;
}

void insert(int id,string& p)
{
    int now = head;
    int c;
    for(int i=0;i<p.length();i++)
    {
        c = p[i] - 'a';
        if(zx[now].to[c] != -1)
        {
            now = zx[now].to[c];
        }
        else
        {
            zx[now].to[c] = get();
            now = zx[now].to[c];
        }
    }
    if(zx[now].id == id)
    {
        assert(false);
    }
    zx[now].id = id;
    return ;
}

void ac()
{
    queue<int>q;
    CL(q);
    q.push(head);
    int now,to,tmp;
    while(!q.empty())
    {
        now = q.front();
        q.pop();
        for(int u=0;u<maxc;u++) if(zx[now].to[u] != -1)
        {
            to = zx[now].to[u];
            q.push(to);
            tmp = now;
            while(tmp)
            {
                tmp = zx[tmp].fail;
                if(zx[tmp].to[u]!=-1)
                {
                    zx[to].fail = zx[tmp].to[u];
                    break;
                }
            }
        }
    }
    return ;
}

int find(int now)
{
    if(ok[now])
    {
        return fs[now];
    }
    else
    {
        int re = 0;
        ok[now] = true;
        if(now)
        {
            if(zx[now].id != -1)
            {
                re |= 1<<zx[now].id;
            }
            re |= find(zx[now].fail);
        }
        fs[now] = re;
        return re;
    }
}

void dps()
{
    dp[0][0][0] = 1;
    as.len = 0;
    as.pos = 0;
    as.s = 0;
    queue<aa>q;
    CL(q);
    q.push(as);
    hash[0][0][0] = true;
    aa now,to;
    int temp;
    while(!q.empty())
    {
        now = q.front();
        q.pop();
        for(int i=0;i<26;i++)
        {
            if(zx[now.pos].to[i] != -1)
            {
                to.pos = zx[now.pos].to[i];
                to.s = find(to.pos) | now.s;
                to.len = now.len + 1;
            }
            else
            {
                temp = now.pos;
                while(temp)
                {
                    temp = zx[temp].fail;
                    if(zx[temp].to[i] != -1)
                    {
                        temp = zx[temp].to[i];
                        break;
                    }
                }
                zx[now.pos].to[i] = temp;
                to.len = now.len+1;
                to.pos = temp;
                to.s = find(temp) | now.s;
            }
            if(to.len <= n)
            {
                dp[to.len][to.pos][to.s] += dp[now.len][now.pos][now.s];
                dp[to.len][to.pos][to.s] %= mod;
                if(!hash[to.len][to.pos][to.s])
                {
                    hash[to.len][to.pos][to.s] = true;
                    q.push(to);
                }
            }
        }
    }
    return ;
}

int has(int temp)
{
    int re = 0;
    for(int i=0;i<m;i++)
    {
        if(temp & (1<<i))
        {
            re++;
        }
    }
    return re;
}

int start()
{
    ac();

    for(int i=0;i<=n;i++)
    {
        for(int j=0;j<=use;j++)
        {
            for(int k=0;k<=(1<<m);k++)
            {
                dp[i][j][k] = 0;
                hash[i][j][k] = false;
            }
        }
    }

    MM(ok,false);

    dps();

    int re = 0;
    for(int i=0;i<=use;i++)
    {
        for(int j=0;j<(1<<m);j++)
        {
            if(has(j)>=k)
            {
                re += dp[n][i][j];
                re %= mod;
            }
        }
    }
    return re;
}

int main()
{
    while(cin>>n>>m>>k)
    {
        if(!n && !m & !k) break;
        use = -1;
        get();
        for(int i=0;i<m;i++)
        {
           // cin>>s;
            scanf("%s",ss);
            s = ss;
            insert(i,s);
        }
       // cout<<start()<<endl;
        printf("%d\n",start());
    }
    return 0;
}