文本生成器(AC自动机上DP)

#include<bits/stdc++.h>
using namespace std;
const int L = 105;
const int mod = 1e4 + 7;
int n, m, cnt, ans = 1, tr[L * 60][30], fail[L * 60], dp[L][L * 60], flag[L * 60];
char s[L];
vector<int> mp[L * 60];
void build(char *s){
	int p = 0;
	for(int i = 0, len = strlen(s); i < len; i++){
		if(!tr[p][s[i] - 'A']) tr[p][s[i] - 'A'] = ++cnt;
		p = tr[p][s[i] - 'A'];
	}
	flag[p] |= 1;
}
void ac(){
	queue<int> q;
	for(int i = 0; i < 26; i++){
		if(!tr[0][i]) continue;
		fail[tr[0][i]] = 0;
		q.push(tr[0][i]);
	}
	while(!q.empty()){
		int u = q.front(); q.pop();
		for(int i = 0; i < 26; i++){
			if(tr[u][i]){
				fail[tr[u][i]] = tr[fail[u]][i];
				flag[tr[u][i]] |= flag[tr[fail[u]][i]];
				q.push(tr[u][i]);
			}
			else tr[u][i] = tr[fail[u]][i];
		}
	}
}
int main(){
	cin >> n >> m;
	for(int i = 1; i <= n; i++){
		cin >> s;
		build(s);
	}
	ac();
	dp[0][0] = 1;
	for(int i = 1; i <= m; i++){
		for(int j = 0; j < 26; j++){
			for(int k = 0; k <= cnt; k++){
				if(!flag[tr[k][j]]) dp[i][tr[k][j]] = (dp[i][tr[k][j]] + dp[i - 1][k]) % mod;
			}
		}
	}
	int sum = 0;
	for(int i = 0; i <= cnt; i++) sum = (sum + dp[m][i]) % mod;
	for(int i = 1; i <= m; i++) ans = (ans * 26) % mod;
	cout << (ans - sum + mod) % mod;
	return 0;
}