hdoj 2243 考研路茫茫——单词情结 【AC自动机 + 构造矩阵】

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
#define MAXN 50
#define LL unsigned long long
using namespace std;
struct Matrix{
LL a[MAXN][MAXN];
LL N;
};
Matrix ori, res;
Matrix multi(Matrix x, Matrix y)
{
Matrix z;
memset(z.a, 0, sizeof(z.a));
z.N = x.N;
for(int i = 0; i < x.N; i++)
{
for(int k = 0; k < y.N; k++)
{
if(x.a[i][k] == 0) continue;
for(int j = 0; j < x.N; j++)
z.a[i][j] += x.a[i][k] * y.a[k][j];
}
}
return z;
}
Matrix M_op(LL n)
{
while(n)
{
if(n & 1)
res = multi(ori, res);
ori = multi(ori, ori);
n >>= 1;
}
}
LL sum(LL n)
{
memset(ori.a, 0, sizeof(ori.a));
memset(res.a, 0, sizeof(res.a));
ori.N = res.N = 2;
for(int i = 0; i < 2; i++)
res.a[i][i] = 1;
ori.a[0][0] = ori.a[0][1] = 1;//构建矩阵 一开始这里写错了，找好久bug
ori.a[1][1] = 26;
if(n == 1)
return 27;
M_op(n-1);
return 27 * res.a[1][1] + res.a[0][1];
}
struct Trie
{
int next[MAXN][30], fail[MAXN], End[MAXN];
int L, root;
int newnode()
{
for(int i = 0; i < 26; i++)
next[L][i] = -1;
End[L++] = 0;
return L-1;
}
void init()
{
L = 0;
root = newnode();
}
void Insert(char *s)
{
int len = strlen(s);
int now = root;
for(int i = 0; i < len; i++)
{
if(next[now][s[i]-'a'] == -1)
next[now][s[i]-'a'] = newnode();
now = next[now][s[i]-'a'];
}
End[now] = 1;
}
void Build()
{
queue<int> Q;
fail[root] = root;
for(int i = 0; i < 26; i++)
{
if(next[root][i] == -1)
next[root][i] = root;
else
{
fail[next[root][i]] = root;
Q.push(next[root][i]);
}
}
while(!Q.empty())
{
int now = Q.front();
Q.pop();
if(End[fail[now]])//失配指针指向模式串
End[now] = 1;//可行
for(int i = 0; i < 26; i++)
{
if(next[now][i] == -1)
next[now][i] = next[fail[now]][i];
else
{
fail[next[now][i]] = next[fail[now]][i];
Q.push(next[now][i]);
}
}
}
}
void getMatrix()
{
for(int i = 0; i < L; i++)
if(End[i] == 0)
for(int j = 0; j < 26; j++)
if(End[next[i][j]] == 0)
ori.a[i][next[i][j]]++;
for(int i = 0; i < L+1; i++)
ori.a[i][L] = 1;
}
};
Trie ac;
void init_M(int NN)
{
memset(ori.a, 0, sizeof(ori.a));
memset(res.a, 0, sizeof(res.a));
ori.N = res.N = NN;
for(int i = 0; i < NN; i++)
res.a[i][i] = 1;
}
LL solve(LL n)
{
M_op(n);
LL ans = 0;
for(int i = 0; i < res.N; i++)
ans += res.a[0][i];
return ans;
}
char str[100];
int main()
{
int N;
LL L;
while(scanf("%d%llu", &N, &L) != EOF)
{
LL ans = sum(L) - 1;//总方案数
ac.init();
for(int i = 0; i < N; i++)
scanf("%s", str), ac.Insert(str);
ac.Build();
init_M(ac.L+1); ac.getMatrix();
LL temp = solve(L) - 1;//不符合方案数
printf("%llu\n", ans - temp);
}
return 0;
}