bzoj1009: [HNOI2008]GT考试

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
#define rep(i,s,t) for(int i=s;i<=t;i++)
#define dwn(i,s,t) for(int i=s;i>=t;i--)
#define clr(x,c) memset(x,c,sizeof(x))
#define ll long long
const int nmax=25;
char s[nmax];
int ch[nmax][10],fail[nmax],F[nmax],pt=0,n,m,mod;
void insert(){
	int t=0,len=strlen(s);
	rep(i,0,len-1) {
		if(!ch[t][s[i]-‘0‘]) ch[t][s[i]-‘0‘]=++pt;
		t=ch[t][s[i]-‘0‘];
	}
	F[t]=1;
}
void getfail(){
	queue<int>q;fail[0]=0;q.push(0);
	while(!q.empty()){
		int x=q.front();q.pop();
		rep(i,0,9) {
			if(ch[x][i]) q.push(ch[x][i]),fail[ch[x][i]]=x==0?0:ch[fail[x]][i];
			else ch[x][i]=x==0?0:ch[fail[x]][i];
		}   
		F[x]|=F[fail[x]];
	}
}
struct node{
	int a[nmax][nmax];
	node(){
		clr(a,0);
	}
	node operator*(const node&o)const {
		node tmp;
		rep(i,0,pt) rep(j,0,pt) rep(k,0,pt) {
			tmp.a[i][j]=(tmp.a[i][j]+a[i][k]*o.a[k][j])%mod;
		}
		return tmp;
	}
}a,b;
void getmatrix(){
	rep(i,0,pt) a.a[i][i]=1;
	rep(i,0,pt) rep(j,0,9) if(!F[ch[i][j]]) b.a[i][ch[i][j]]++;
	while(n){
		if(n&1) a=a*b;
		b=b*b;n>>=1;
	}
	int ans=0;
	rep(i,0,pt) ans=(ans+a.a[0][i])%mod;
	printf("%d\n",ans);
}
int main(){
	scanf("%d%d%d",&n,&m,&mod);
	scanf("%s",s);insert();getfail();
	//rep(i,0,pt) printf("%d ",fail[i]);printf("\n");
	//rep(i,0,pt) printf("%d ",F[i]);printf("\n");
	getmatrix();
	return 0;
}