AC自动机模板

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<queue>
#include<algorithm>
using namespace std;
const int maxn=1e6+50;
int n;
char str[500][500];
char qry[maxn];
struct Auto_AC
{
    int tr[maxn][26],val[maxn],fail[maxn],cnt[maxn],fa[maxn];
    int Size;
    inline void init()
    {
        Size=0;
        memset(val,0,sizeof(val));
        memset(fail,0,sizeof(fail));
        memset(cnt,0,sizeof(cnt));
        memset(fa,0,sizeof(fa));
        memset(tr,0,sizeof(tr));
    }
    inline void add(char s[],int ind)
    {
        int now=0,k,len=strlen(s);
        for(int i=0;i<len;i++)
        {
            k=s[i]-'a';
            if(!tr[now][k])tr[now][k]=++Size;
            now=tr[now][k];
        }
        val[now]=ind;
    }
    inline void makefail()
    {
        queue<int> q;
        q.push(0);
        int now,k,v;
        while(!q.empty())
        {
            now=q.front();k=fa[now];q.pop();
            for(int cc=0;cc<=25;cc++)
            {
                v=tr[now][cc];
                if(!v){tr[now][cc]=tr[k][cc];continue;}
                fa[v]=now ? tr[k][cc] : 0;
                fail[v]=val[fa[v]]?fa[v]:fail[fa[v]];
                q.push(v);
            }
        }
    }
    inline void query(char s[])
    {
        int now=0,len=strlen(s),ans=0,k,v;
        for(int i=0;i<len;i++)
        {
            k=s[i]-'a';
            now=tr[now][k];
            if(val[now])cnt[val[now]]++;
            v=fail[now];
            while(v)
            {
                if(val[v])cnt[val[v]]++;
                v=fail[v];
            }
        }
        for(int i=1;i<=n;i++)ans=max(ans,cnt[i]);
        printf("%d
",ans);
        for(int i=1;i<=n;i++)if(cnt[i]==ans)printf("%s
",str[i]);
    }
}Machine;
int main()
{
    while(scanf("%d",&n) && n)
    {
        Machine.init();
        for(int i=1;i<=n;i++)
        {
            scanf("%s",str[i]);
            Machine.add(str[i],i);
        }
        Machine.makefail();
        scanf("%s",qry);
        Machine.query(qry);
    }
}
Luogu 3796 加强版
#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<queue>
#include<algorithm>
using namespace std;
const int maxn=500010;
int n;
char str[1000005];
char qry[1000005];
struct Auto_AC
{
    int tr[maxn][26],val[maxn],fail[maxn],cnt[maxn],fa[maxn];
    int Size;
    inline void init()
    {
        Size=0;
        memset(val,0,sizeof(val));
        memset(fail,0,sizeof(fail));
        memset(cnt,0,sizeof(cnt));
        memset(fa,0,sizeof(fa));
        memset(tr,0,sizeof(tr));
    }
    inline void add(char s[])
    {
        int now=0,k,len=strlen(s);
        for(int i=0;i<len;i++)
        {
            k=s[i]-'a';
            if(!tr[now][k])tr[now][k]=++Size;
            now=tr[now][k];
        }
        val[now]++;
    }
    inline void makefail()
    {
        queue<int> q;
        q.push(0);
        int now,k,v;
        while(!q.empty())
        {
            now=q.front();k=fa[now];q.pop();
            for(int cc=0;cc<=25;cc++)
            {
                v=tr[now][cc];
                if(!v){tr[now][cc]=tr[k][cc];continue;}
                fa[v]=now ? tr[k][cc] : 0;
                fail[v]=val[fa[v]]?fa[v]:fail[fa[v]];
                q.push(v);
            }
        }
    }
    inline int query(char s[])
    {
        int now=0,len=strlen(s),ans=0,k,v;
        for(int i=0;i<len;i++)
        {
            k=s[i]-'a';now=tr[now][k];
            for(int t=now;t && ~val[t];t=fail[t])ans+=val[t],val[t]=-1;
        }
        return ans;
    }
}Machine;
int main()
{
    scanf("%d",&n);
    //Machine.init();
    for(int i=1;i<=n;i++)
    {
        scanf("%s",str);
        Machine.add(str);
    }
    Machine.makefail();
    scanf("%s",qry);
    cout<<Machine.query(qry);
}
原文地址:https://www.cnblogs.com/Kong-Ruo/p/8177257.html