CF1163D Mysterious Code（AC自动机+dp）

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=5e5+10;
struct node{
    int cnt;
    node * nxt[27];
    node * fail;
    vector<node *> num;
}*rt;
node pool[N];
int n,idx;
int val[N];
int num;
int f[1100][200];
void insert(string s,int x){
    node *p=rt;
    int i;
    for(i=0;i<s.size();i++){
        int sign=s[i]-‘a‘;
        if(p->nxt[sign]==NULL){
            p->nxt[sign]=pool+(++idx);
            p->nxt[sign]->cnt=++num;
        }
        p=p->nxt[sign];
        if(i==(int)s.size()-1){
            val[p->cnt]=x;
        }
    }
}
void build(){
    int i;
    queue<node *> q;
    rt->fail=rt;
    for(i=0;i<26;i++){
        if(rt->nxt[i]){
            rt->nxt[i]->fail=rt;
            rt->num.push_back(rt->nxt[i]);
            q.push(rt->nxt[i]);
        }
        else{
            rt->nxt[i]=rt;
            rt->nxt[i]->fail=rt;
        }
    }
    while(q.size()){
        auto t=q.front();
        q.pop();
        for(i=0;i<26;i++){
            if(t->nxt[i]){
                t->nxt[i]->fail=t->fail->nxt[i];
                t->fail->nxt[i]->num.push_back(t->nxt[i]);
                q.push(t->nxt[i]);
            }
            else{
                t->nxt[i]=t->fail->nxt[i];
            }
        }
        val[t->cnt]+=val[t->fail->cnt];
    }
}
int main(){
    ios::sync_with_stdio(false);
    int i;
    rt=pool;
    rt->cnt=0;
    string c;
    cin>>c;
    n=c.size();
    c=" "+c;
    string s,t;
    cin>>s>>t;
    insert(s,1);
    insert(t,-1);
    build();
    memset(f,-0x3f,sizeof f);
    f[0][0]=0;
    for(i=1;i<=n;i++){
        for(int j=0;j<=num;j++){
            for(int k=0;k<26;k++){
                if(c[i]==‘*‘||(c[i]==‘a‘+k)){
                    int id=(pool+j)->nxt[k]->cnt;
                    f[i][id]=max(f[i][id],f[i-1][j]+val[id]);
                }
            }
        }
    }
    int ans=-0x3f3f3f3f;
    for(i=0;i<=num;i++)
        ans=max(ans,f[n][i]);
    cout<<ans<<endl;
}