题面
Sol
(AC)自动机上(DP)
总数(-)不合法
# include <bits/stdc++.h>
# define RG register
# define IL inline
# define Fill(a, b) memset(a, b, sizeof(a))
using namespace std;
typedef long long ll;
const int _(6005);
const int Zsy(10007);
IL ll Input(){
RG ll x = 0, z = 1; RG char c = getchar();
for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1;
for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
return x * z;
}
int n, m, ans = 1, ch[26][_], fail[_], ed[_], tot, f[500][_];
queue <int> Q;
char s[_];
IL void Insert(){
RG int l = strlen(s), x = 0;
for(RG int i = 0; i < l; ++i){
RG int id = s[i] - 'A';
if(!ch[id][x]) ch[id][x] = ++tot;
x = ch[id][x];
}
ed[x] = 1;
}
IL void BuildFail(){
for(RG int i = 0; i < 26; ++i) if(ch[i][0]) Q.push(ch[i][0]);
while(!Q.empty()){
RG int u = Q.front(); Q.pop();
for(RG int i = 0; i < 26; ++i)
if(!ch[i][u]) ch[i][u] = ch[i][fail[u]];
else fail[ch[i][u]] = ch[i][fail[u]], Q.push(ch[i][u]);
ed[u] |= ed[fail[u]];
}
}
IL void Chk1(RG int &x, RG int y){
x += y;
if(x >= Zsy) x -= Zsy;
}
IL void Chk2(RG int &x, RG int y){
x -= y;
if(x < 0) x += Zsy;
}
int main(RG int argc, RG char* argv[]){
n = Input(), m = Input();
for(RG int i = 1; i <= m; ++i) ans = ans * 26 % Zsy;
for(RG int i = 1; i <= n; ++i) scanf(" %s", s), Insert();
BuildFail(), f[0][0] = 1;
for(RG int i = 0; i < m; ++i)
for(RG int j = 0; j <= tot; ++j){
if(!f[i][j] || ed[j]) continue;
for(RG int k = 0; k < 26; ++k)
if(!ed[ch[k][j]]) Chk1(f[i + 1][ch[k][j]], f[i][j]);
}
for(RG int i = 0; i <= tot; ++i) if(!ed[i]) Chk2(ans, f[m][i]);
printf("%d
", ans);
return 0;
}