codeforces291E Tree-String Problem

//It is made by ljh2000
//有志者，事竟成，破釜沉舟，百二秦关终属楚；苦心人，天不负，卧薪尝胆，三千越甲可吞吴。
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <ctime>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <string>
#include <complex>
#include <bitset>
using namespace std;
typedef long long LL;
typedef long double LB;
typedef complex<double> C;
const double pi = acos(-1);
const int MAXN = 600011;
const int MAXM = 1200011;
const int mod = 52013147;
const int base = 29;
int n,m,tot,ecnt,father[MAXN],first[MAXN],to[MAXM],next[MAXM],f[MAXN][20],deep[MAXN],ans;
LL mo[MAXN],g[MAXN][20],Ha;
char s[MAXN];
inline void link(int x,int y){ next[++ecnt]=first[x]; first[x]=ecnt; to[ecnt]=y; }
inline int getint(){
    int w=0,q=0; char c=getchar(); while((c<‘0‘||c>‘9‘) && c!=‘-‘) c=getchar();
    if(c==‘-‘) q=1,c=getchar(); while (c>=‘0‘&&c<=‘9‘) w=w*10+c-‘0‘,c=getchar(); return q?-w:w;
}

inline void init(){
	mo[0]=1; for(int i=1;i<=600000;i++) mo[i]=mo[i-1]*base,mo[i]%=mod;
	for(int j=1;j<=19;j++)
		for(int i=1;i<=tot;i++) {
			f[i][j]=f[f[i][j-1]][j-1];
			g[i][j]=( g[i][j-1]*mo[(1<<(j-1))] + g[f[i][j-1]][j-1] )%mod;
		}
}

inline bool check(int x){
	LL now=0; int remain=m;
	for(int i=19;i>=0;i--)
		if(remain>=(1<<i))
			now=(now*mo[(1<<i)]+g[x][i])%mod,x=f[x][i],remain-=(1<<i);
	if(now==Ha) return true;
	return false;
}

inline void dfs(int x,int fa){
	if(deep[x]>=m) {
		if(check(x)) 
			ans++;
	}
	for(int i=first[x];i;i=next[i]) {
		int v=to[i]; if(v==fa) continue;
		deep[v]=deep[x]+1; dfs(v,x);
	}
}

inline void work(){
	n=tot=getint(); int len,last;
	for(int i=2;i<=n;i++) {
		father[i]=getint();
		scanf("%s",s+1); len=strlen(s+1);
		last=father[i];
		for(int j=1;j<len;j++) {
			tot++;
			f[tot][0]=last;
			g[tot][0]=s[j]-‘a‘+1;
			link(last,tot);
			last=tot;
		}
		link(last,i);
		f[i][0]=last;/*!!!*/
		g[i][0]=s[len]-‘a‘+1;
	}
	init();
	scanf("%s",s+1); m=strlen(s+1);
	Ha=0;
	for(int i=m;i>=1;i--) Ha=Ha*base+s[i]-‘a‘+1,Ha%=mod;
	dfs(1,0);
	printf("%d",ans);
}

int main()
{
    work();
    return 0;
}
//有志者，事竟成，破釜沉舟，百二秦关终属楚；苦心人，天不负，卧薪尝胆，三千越甲可吞吴。