【bzoj1030】 JSOI2007—文本生成器

// bzoj1030
#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<queue>
#define LL long long
#define inf (1ll<<30)
#define MOD 10007
#define Pi acos(-1.0)
#define free(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout)
using namespace std;

const int maxl=200,maxn=60;
int n,m,sz=1,f[maxl][maxn*maxl];
char s[maxl];
struct node {
	int son[26],next,end;
	int& operator [] (int x) {return son[x];}
}tr[maxn*maxl];

namespace ACM {
	void insert(char *r) {
		int len=strlen(r+1),p=1;
		for (int i=1;i<=len;i++) {
			if (!tr[p][r[i]-‘A‘]) tr[p][r[i]-‘A‘]=++sz;
			p=tr[p][r[i]-‘A‘];
		}
		tr[p].end=1;
	}
	void buildfail() {
		queue<int> q;q.push(1);
		tr[1].next=0;
		while (!q.empty()) {
			int x=q.front();q.pop();
			for (int i=0;i<26;i++) if (tr[x][i]) {
					int k=tr[x].next;
					while (!tr[k][i]) k=tr[k].next;
					tr[tr[x][i]].next=tr[k][i];
					tr[tr[x][i]].end|=tr[tr[k][i]].end;
					q.push(tr[x][i]);
				}
		}
	}
}
using namespace ACM;
	
int main() {
	scanf("%d%d",&n,&m);
	for (int i=0;i<26;i++) tr[0][i]=1;
	for (int i=1;i<=n;i++) {
		scanf("%s",s+1);
		insert(s);
	}
	buildfail();
	f[0][1]=1;
	for (int i=0;i<m;i++)
		for (int j=1;j<=sz;j++) if (f[i][j]) {
				for (int k=0;k<26;k++) {
					int p=j;
					while (!tr[p][k]) p=tr[p].next;
					p=tr[p][k];
					if (!tr[p].end) (f[i+1][p]+=f[i][j])%=MOD;
				}
			}
	int sum=1,ans=0;
	for (int i=1;i<=m;i++) (sum*=26)%=MOD;
	for (int i=1;i<=sz;i++) (ans+=f[m][i])%=MOD;
	printf("%d\n",(sum-ans+MOD)%MOD);
	return 0;
}