Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 5640 Accepted Submission(s): 1785
/*
hdu 2825 aC自动机+状压dp
给你m个子串,求长度为n的主串中至少出现k个子串的方案数
首先通过AC自动机构建关系图. 然后用dp解决状态转移,需要知道用过哪些子串
因为k比较小,我们直接转换成二进制来记录当前状态包含了哪些子串。用ed对各子串进行标记
dp[i][j][t]就表示长度为i,当前位置上是j时,所包含子串的情况t
hhh-2016-04-24 17:13:36
*/
#include <iostream>
#include <vector>
#include <cstring>
#include <string>
#include <cstdio>
#include <queue>
#include <algorithm>
#include <functional>
#include <map>
using namespace std;
#define lson (i<<1)
#define rson ((i<<1)|1)
typedef unsigned long long ll;
typedef unsigned int ul;
const int mod = 20090717;
const int INF = 0x3f3f3f3f;
int tot;
int dp[30][111][1<<10];
struct Matrix
{
int len;
int ma[111][111];
Matrix() {};
Matrix(int L)
{
len = L;
}
};
struct Tire
{
int nex[110][26],fail[110],ed[110];
int root,L;
int newnode()
{
for(int i = 0; i < 26; i++)
nex[L][i] = -1;
ed[L++] = 0;
return L-1;
}
void ini()
{
L = 0,root = newnode();
}
int cal(char ch)
{
if(ch == ‘A‘)
return 0;
else if(ch == ‘C‘)
return 1;
else if(ch == ‘G‘)
return 2;
else if(ch == ‘T‘)
return 3;
}
void inser(char buf[],int id)
{
int len = strlen(buf);
int now = root;
for(int i = 0; i < len; i++)
{
int ta = buf[i] - ‘a‘;
if(nex[now][ta] == -1)
nex[now][ta] = newnode();
now = nex[now][ta];
}
ed[now] |= (1<<id);
}
void build()
{
queue<int >q;
fail[root] = root;
for(int i = 0; i < 26; i++)
if(nex[root][i] == -1)
nex[root][i] = root;
else
{
fail[nex[root][i]] = root;
q.push(nex[root][i]);
}
while(!q.empty())
{
int now = q.front();
q.pop();
if(ed[fail[now]])
ed[now] |= ed[fail[now]];
for(int i = 0; i < 26; i++)
{
if(nex[now][i] == -1)
nex[now][i] = nex[fail[now]][i];
else
{
fail[nex[now][i]] = nex[fail[now]][i];
q.push(nex[now][i]);
}
}
}
}
Matrix to_mat()
{
Matrix mat(L);
memset(mat.ma,0,sizeof(mat.ma));
for(int i = 0; i < L; i++)
{
for(int j = 0; j < 4; j++)
{
if(!ed[nex[i][j]])
mat.ma[i][nex[i][j]] ++;
}
}
return mat;
}
};
//Matrix mat;
Tire ac;
char buf[22];
void debug()
{
Matrix t = ac.to_mat();
for(int i = 0; i < t.len; i++)
{
for(int j = 0; j < 26; j++)
{
printf("%d ",t.ma[i][ac.nex[i][j]]);
}
printf("\n");
}
}
int num[1<<10];
int main()
{
for(int i=0; i<(1<<10); i++)
{
num[i] = 0;
for(int j = 0; j < 10; j++)
if(i & (1<<j))
num[i]++;
}
int n,m,p;
while(scanf("%d%d%d",&n,&m,&p) != EOF)
{
if(!n && !m && !p)
break;
ac.ini();
for(int i = 0; i < m; i++)
{
scanf("%s",buf);
ac.inser(buf,i);
}
ac.build();
for(int i = 0; i <= n; i++)
{
for(int j = 0; j <ac.L; j++)
{
for(int k = 0; k < (1<<m); k++)
dp[i][j][k] = 0;
}
}
dp[0][0][0] = 1;
for(int i = 0; i < 2; i++)
{
for(int j = 0; j < ac.L; j++)
{
for(int t = 0; t < (1<<m); t++)
{
if(dp[i][j][t] > 0)
for(int k = 0; k < 26; k++)
{
int nexi = i+1;
int nexj = ac.nex[j][k];
int nexk = (t|ac.ed[nexj]);
dp[nexi][nexj][nexk] = (dp[nexi][nexj][nexk] + dp[i][j][t])%mod;
}
}
}
}
int ans = 0;
for(int j = 0; j < (1<<m); j++)
{
if(num[j] < p)
continue;
for(int i = 0; i < ac.L; i++)
ans = (ans+dp[n][i][j])%mod;
}
printf("%d\n",ans);
}
return 0;
}
原文:http://www.cnblogs.com/Przz/p/5449315.html