http://poj.org/problem?id=2778
AC自動機 + 矩陣連乘
代碼:
#include<iostream>
#include<cmath>
#include<cstdio>
#include<string>
#include<cstring>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<algorithm>#define LL long longusing namespace std;const int INF=0x3f3f3f3f;
const int MOD=100000;
const LL LMOD=100000;
const int N=1005;
const int M=1005;
const int K=4;
const int MATRIXN=5;
const int MATRIXM=115;
const int MATRIXH=115;
struct nodeTrie
{int v;int fail;int next[K];void initialize(){v=0;fail=-1;memset(next,-1,sizeof(next));}
}trie[M];
int cnt,root;
char s[N];
LL ma[MATRIXN][MATRIXM],mb[MATRIXM][MATRIXH],mc[MATRIXM][MATRIXH];
int getNewNode()
{++cnt;trie[cnt].initialize();return cnt;
}
void addWord(int p,char *s,int k)
{if(s[0]=='\0') return ;for(int i=0;s[i]!='\0';++i){if(trie[p].next[s[i]-'A']==-1)trie[p].next[s[i]-'A']=getNewNode();p=trie[p].next[s[i]-'A'];}(trie[p].v)=k;
}
void init(int n)
{cnt=0;root=getNewNode();for(int i=0;i<4;++i){s[0]='A'+i;s[1]='\0';addWord(root,s,0);}while(n--){gets(s);for(int i=0;s[i]!='\0';++i){if(s[i]=='C')s[i]='B';else if(s[i]=='G')s[i]='C';else if(s[i]=='T')s[i]='D';}addWord(root,s,1);}
}
void bfs(int p)
{trie[p].fail=root;queue<int>qt;qt.push(p);while(!qt.empty()){int y;int x=qt.front();qt.pop();for(int i=0;i<K;++i)if(trie[x].next[i]!=-1){qt.push(trie[x].next[i]);if(x==root){trie[trie[x].next[i]].fail=root;continue;}y=trie[x].fail;while(y!=root&&trie[y].next[i]==-1)y=trie[y].fail;if(trie[y].next[i]!=-1)trie[trie[x].next[i]].fail=trie[y].next[i];elsetrie[trie[x].next[i]].fail=root;}}
}
void makeMatrix(LL a[][MATRIXM],int n)
{for(int i=1;i<=n;++i)for(int j=1;j<=n;++j)a[i][j]=0;for(int i=1;i<=n;++i)for(int j=0;j<4;++j){//cout<<i<<endl;int p=i;int q=0;while(p!=root&&trie[p].next[j]==-1)p=trie[p].fail;if(trie[p].next[j]!=-1)q=trie[p].next[j];int w=q;bool flag=true;while(w!=root){if(trie[w].v>0){flag=false;break;}w=trie[w].fail;}if(trie[w].v>0)flag=false;if(flag==true)a[i][q]=1;}
}
void matrixMul(LL a[][MATRIXM],LL b[][MATRIXM],int n,int m,int h)
{for(int i=1;i<=n;++i)for(int j=1;j<=h;++j){LL tmp=0;for(int l=1;l<=m;++l)tmp=(tmp+a[i][l]*b[l][j])%LMOD;mc[i][j]=tmp;}for(int i=1;i<=n;++i)for(int j=1;j<=h;++j)a[i][j]=mc[i][j];
}
int main()
{//freopen("data.in","r",stdin);int n,m;while(scanf("%d %d ",&n,&m)!=EOF){init(n);bfs(root);int MN=1,MM=cnt,MH=cnt;makeMatrix(mb,MM);memset(ma,0,sizeof(ma));ma[1][1]=1;while(m>0){if((m&1)==1)matrixMul(ma,mb,MN,MM,MH);matrixMul(mb,mb,MM,MM,MH);m=(m>>1);}LL ans=0;for(int i=1;i<=MN;++i)for(int j=1;j<=MM;++j)ans=(ans+ma[i][j])%LMOD;cout<<ans<<endl;}return 0;
}