http://poj.org/problem?id=2778
有空再又一次做下，对状态图的理解非常重要
题解：
http://blog.csdn.net/morgan_xww/article/details/7834801
另外做了矩阵幂的模板：
//ac.sz是矩阵的大小
void mulmtr(long long x[MAXNODE][MAXNODE],long long y[MAXNODE][MAXNODE])//y=x*y
{ll tmp[MAXNODE][MAXNODE];for(int i=0;i<ac.sz;i++){for(int j=0;j<ac.sz;j++){tmp[i][j]=0;for(int k=0;k<ac.sz;k++)tmp[i][j] +=x[i][k]*y[k][j];tmp[i][j] %=MOD;}}for(int i=0;i<ac.sz;i++)for(int j=0;j<ac.sz;j++)y[i][j]=tmp[i][j];
}
void Mtrmi(ll mtr[MAXNODE][MAXNODE],int n)
{for(int i=0;i<ac.sz;i++){for(int j=0;j<ac.sz;j++){if(i == j)ans[i][j]=1;//E矩阵else ans[i][j]=0;}}while(n){if(n&1){mulmtr(mtr,ans);}mulmtr(mtr,mtr);n/=2;}
}
代码：
#include <cstdio>
#include <cstring>
#include <string>
#include <map>
#include <queue>
#include <iostream>
using namespace std;#define ll long longconst int MAXNODE = 15*15;
const int SSIZE = 2000000000+100;
const int MOD = 100000;
const int SIGMA_SIZE = 4;
const int SIZE = 20;ll mtr[MAXNODE][MAXNODE];
ll ans[MAXNODE][MAXNODE];
int danger[MAXNODE];struct AC
{int f[MAXNODE];int val[MAXNODE];int last[MAXNODE];int cnt[MAXNODE];int ch[MAXNODE][SIGMA_SIZE];int sz;void init(){memset(ch[0],0,sizeof(ch[0]));memset(cnt,0,sizeof(cnt));f[0]=0;///sz=1;}inline int idx(char x){if(x == 'A')return 0;if(x == 'T')return 1;if(x == 'C')return 2;if(x == 'G')return 3;}void insert(char *s, int v){int n=strlen(s),u=0;for(int i=0;i<n;i++){int id= idx(s[i]);if(!ch[u][id]){memset(ch[sz],0,sizeof(ch[sz]));val[sz]=0;ch[u][id]=sz++;}u=ch[u][id];}val[u]=v;danger[u]=1;}void getfail(){queue<int>q;f[0]=0;for(int c=0;c<SIGMA_SIZE;c++){int u=ch[0][c];if(u){q.push(u);f[u]=0;last[u]=0;}}while(!q.empty()){int r=q.front();q.pop();for(int c=0;c<SIGMA_SIZE;c++){int u=ch[r][c];//if(!u)continue;if(!u){ch[r][c]=ch[f[r]][c];//continue;}q.push(u);int v=f[r];while(v &&!ch[v][c])v=f[v];f[u]=ch[v][c];//last[u]=val[f[u]]?f[u]:last[f[u]];danger[u] |= danger[f[u]];}}}
};
void init()
{memset(mtr,0,sizeof(mtr));memset(danger,0,sizeof(danger));
}AC ac;char str[SIZE];void mulmtr(long long x[MAXNODE][MAXNODE],long long y[MAXNODE][MAXNODE])//y=x*y
{ll tmp[MAXNODE][MAXNODE];for(int i=0;i<ac.sz;i++){for(int j=0;j<ac.sz;j++){tmp[i][j]=0;for(int k=0;k<ac.sz;k++)tmp[i][j] +=x[i][k]*y[k][j];tmp[i][j] %=MOD;}}for(int i=0;i<ac.sz;i++)for(int j=0;j<ac.sz;j++)y[i][j]=tmp[i][j];
}
void Mtrmi(ll mtr[MAXNODE][MAXNODE],int n)
{for(int i=0;i<ac.sz;i++){for(int j=0;j<ac.sz;j++){if(i == j)ans[i][j]=1;//E矩阵else ans[i][j]=0;}}while(n){if(n&1){mulmtr(mtr,ans);}mulmtr(mtr,mtr);n/=2;}
}int main()
{//freopen("poj2788.txt","r",stdin);int n,m;while(~scanf("%d%d",&m,&n)){init();ac.init();for(int i=1;i<=m;i++){scanf("%s",str);ac.insert(str,i);}ac.getfail();for(int i=0;i<ac.sz;i++)if(!danger[i])for(int j=0;j<4;j++)if(!danger[ac.ch[i][j]]){mtr[i][ac.ch[i][j]]++;}Mtrmi(mtr,n);//* for(int i=0;i<ac.sz;i++){for(int j=0;j<ac.sz;j++)printf("%lld|%lld ",mtr[i][j],ans[i][j]);putchar('\n');}*////for(int i=1;i<ac.sz;i++)ans[0][0]+=ans[0][i]%MOD;printf("%I64d\n",ans[0][0]%MOD);}return 0;
}
