LOJ6583 ICPC World Finals 2019何以伊名始（广义后缀自动机）

　　对trie建SAM，询问串倒过来跑到的节点的|right|即为答案。

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define inf 1000000010
#define N 2000010
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{
	int x=0,f=1;char c=getchar();
	while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}
	while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();
	return x*f;
}
int n,m,trie[N][26],son[N][26],fail[N],len[N],size[N],tmp[N],id[N],q[N],cnt=1;
char s[N];
int ins(int c,int p)
{
    int x=++cnt;len[x]=len[p]+1;size[x]=1;
    while (!son[p][c]&&p) son[p][c]=x,p=fail[p];
    if (!p) fail[x]=1;
    else
    {
        int q=son[p][c];
        if (len[p]+1==len[q]) fail[x]=q;
        else
        {
            int y=++cnt;
            len[y]=len[p]+1;
            memcpy(son[y],son[q],sizeof(son[q]));
            fail[y]=fail[q],fail[x]=fail[q]=y;
            while (son[p][c]==q) son[p][c]=y,p=fail[p];
        }
    }
    return x;
}
int run(char *s)
{
	int n=strlen(s+1);
	int k=1;for (int i=n;i>=1;i--) k=son[k][s[i]-'A'];
	return k;
}
signed main()
{
#ifndef ONLINE_JUDGE
	freopen("a.in","r",stdin);
	freopen("a.out","w",stdout);
#endif
	n=read(),m=read();
	for (int i=1;i<=n;i++)
	{
		char c=getc();int x=read();
		trie[x][c-'A']=i;
	}
	int head=0,tail=1;q[1]=0;id[0]=1;
	do
	{
		int x=q[++head];
		for (int i=0;i<26;i++)
		if (trie[x][i])
		{
			q[++tail]=trie[x][i];
			id[q[tail]]=ins(i,id[x]);
		}
	}while (head<tail);
	for (int i=1;i<=cnt;i++) tmp[len[i]]++;
	for (int i=1;i<=cnt;i++) tmp[i]+=tmp[i-1];
	for (int i=1;i<=cnt;i++) q[tmp[len[i]]--]=i;
	for (int i=cnt;i>=2;i--) size[fail[q[i]]]+=size[q[i]];
	while (m--)
	{
		scanf("%s",s+1);
		printf("%d
",size[run(s)]);
	}
	return 0;
	//NOTICE LONG LONG!!!!!
}