HDU-2825 Wireless Password(AC自动机+状压DP)

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

typedef long long LL;

const int mod=20090717;

int ch[105][26];
int cnt,fail[105];
int val[105];

void init()
{
cnt=0;
memset(ch,-1,sizeof(ch));
memset(val,0,sizeof(val));
}

int idx(char x)
{
return x-'a';
}

void insert(char *s,int k)
{
int len=strlen(s);
int r=0;
for(int i=0;i<len;++i){
int c=idx(s[i]);
if(ch[r][c]==-1) ch[r][c]=++cnt;
r=ch[r][c];
}
val[r]|=(1<<k);
}

void getFail()
{
queue<int>q;
fail[0]=0;
for(int i=0;i<26;++i){
if(ch[0][i]==-1)
ch[0][i]=0;
else{
fail[ch[0][i]]=0;
q.push(ch[0][i]);
}
}
while(!q.empty())
{
int u=q.front();
q.pop();
val[u]|=val[fail[u]];
for(int i=0;i<26;++i){
if(ch[u][i]==-1)
ch[u][i]=ch[fail[u]][i];
else{
fail[ch[u][i]]=ch[fail[u]][i];
q.push(ch[u][i]);
}
}
}
}

char word[15];
int dp[2][105][1<<10];

int getDigt(int x,int n)
{
int count=0;
for(int i=0;i<n;++i)
if(x&(1<<i)) ++count;
return count;
}

int DP(int n,int m,int k)
{
memset(dp,0,sizeof(dp));
int cur=1;
dp[0][0][0]=1;
for(int i=0;i<n;++i){
memset(dp[cur],0,sizeof(dp[cur]));
for(int j=0;j<=cnt;++j){
for(int s=0;s<(1<<m);++s) if(dp[cur^1][j][s]){	///不加if语句会超时
for(int c=0;c<26;++c){
int &nxt=dp[cur][ch[j][c]][s|val[ch[j][c]]];
nxt=(nxt+dp[cur^1][j][s])%mod;
}
}
}
cur^=1;
}
int ans=0;
for(int i=0;i<(1<<m);++i) if(getDigt(i,m)>=k){
for(int j=0;j<=cnt;++j)
ans=(ans+dp[cur^1][j][i])%mod;
}
return ans;
}

int main()
{
int n,m,k;
while(scanf("%d%d%d",&n,&m,&k)&&(n||m||k))
{
init();
for(int i=0;i<m;++i){
scanf("%s",word);
insert(word,i);
}
getFail();
printf("%d\n",DP(n,m,k));
}
return 0;
}