P7456 [CERC2018] The ABCD Murderer 题解

#include<bits/stdc++.h>
using namespace std;
const int N=300005,S=26;
int trie[N][S],fail[N],f[N],is[N],n,m,k,ans=1;
char s[N],t[N];
void init()
{
	queue<int>q{};
	q.emplace(0);
	int u;
	while(!q.empty())
	{
		u=q.front(),is[u]=max(is[u],is[fail[u]]),q.pop();
		for(int i=0;i<26;++i)
			if(!trie[u][i])
				trie[u][i]=trie[fail[u]][i];
			else
				fail[trie[u][i]]=u==0?0:trie[fail[u]][i],q.emplace(trie[u][i]);
	}
}
int main()
{
	ios::sync_with_stdio(0),cin.tie(0);
	cin>>m>>s+1,n=strlen(s+1);
	int len,u,v;
	for(int i=1;i<=m;++i)
	{
		cin>>t+1,len=strlen(t+1);
		u=0;
		for(int j=1;j<=len;++j)
		{
			if(!trie[u][t[j]-'a'])
				trie[u][t[j]-'a']=++k;
			u=trie[u][t[j]-'a'];
		}
		is[u]=len;
	}
	init();
	u=0;
	for(int i=1;i<=n;++i)
	{
		u=trie[u][s[i]-'a'];
		f[i]=i-is[u];
	}
	u=v=f[n];
	if(f[n]==n)
	{
		cout<<"-1";
		return 0;
	}
	for(int i=n-1;i>=1;--i)
	{
		v=min(v,f[i]);
		if(i==u)
		{
			if(v>=u)
			{
				cout<<"-1";
				return 0;
			}
			u=v,++ans;
		}
	}
	cout<<ans;
	return 0;
}