BZOJ4199 NOI2015品酒大会（后缀树）

　　利用SAM建出后缀树，树上每个节点计算一下|right|、right集合中a_i的最大、次大、最小、次小值即可。

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
#define N 600010
#define inf 1000000010
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,a[N],son[N][26],fail[N],len[N],size[N],mx[N],mx2[N],mn[N],mn2[N],cnt=1,last=1;
ll ans[N],tot[N];
char s[N];
int p[N],t;
struct data{int to,nxt;
}edge[N<<1];
void addedge(int x,int y){t++;edge[t].to=y,edge[t].nxt=p[x],p[x]=t;}
void ins(int c)
{
	int x=++cnt,p=last;last=x;len[x]=len[p]+1;size[x]=1;mx[x]=mn[x]=a[len[x]];mx2[x]=-inf,mn2[x]=inf;
	while (!son[p][c]) 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;mx[y]=mx2[y]=-inf,mn[y]=mn2[y]=inf;
			len[y]=len[p]+1;
			memcpy(son[y],son[q],sizeof(son[q]));
			fail[y]=fail[q],fail[q]=fail[x]=y;
			while (son[p][c]==q) son[p][c]=y,p=fail[p];
		}
	}
}
void dfs(int k)
{
	for (int i=p[k];i;i=edge[i].nxt)
	{
		dfs(edge[i].to);
		size[k]+=size[edge[i].to];
		tot[len[k]]-=1ll*size[edge[i].to]*(size[edge[i].to]-1)>>1;
		if (mx2[edge[i].to]>mx[k]) mx[k]=mx[edge[i].to],mx2[k]=mx2[edge[i].to];
		else if (mx[edge[i].to]>mx[k]) mx2[k]=max(mx2[edge[i].to],mx[k]),mx[k]=mx[edge[i].to];
		else mx2[k]=max(mx2[k],mx[edge[i].to]);
		if (mn2[edge[i].to]<mn[k]) mn[k]=mn[edge[i].to],mn2[k]=mn2[edge[i].to];
		else if (mn[edge[i].to]<mn[k]) mn2[k]=min(mn2[edge[i].to],mn[k]),mn[k]=mn[edge[i].to];
		else mn2[k]=min(mn2[k],mn[edge[i].to]);
	}
	tot[len[k]]+=1ll*size[k]*(size[k]-1)>>1;
	if (mx2[k]>-inf) ans[len[k]]=max(ans[len[k]],1ll*mx[k]*mx2[k]);
	if (mn2[k]<inf) ans[len[k]]=max(ans[len[k]],1ll*mn[k]*mn2[k]);
}
int main()
{
#ifndef ONLINE_JUDGE
	freopen("a.in","r",stdin);
	freopen("a.out","w",stdout);
	const char LL[]="%I64d\n";
#else
	const char LL[]="%lld\n";
#endif
	n=read();mx[1]=mx2[1]=-inf,mn[1]=mn2[1]=inf;
	scanf("%s",s+1);reverse(s+1,s+n+1);
	for (int i=1;i<=n;i++) a[i]=read();reverse(a+1,a+n+1);
	for (int i=1;i<=n;i++) ins(s[i]-'a');
	for (int i=2;i<=cnt;i++) addedge(fail[i],i);
	memset(ans,200,sizeof(ans));
	dfs(1);
	for (int i=n-1;i>=0;i--) ans[i]=max(ans[i],ans[i+1]),tot[i]+=tot[i+1];
	for (int i=0;i<n;i++) if (tot[i]==0) ans[i]=0;
	for (int i=0;i<n;i++) printf("%lld %lld\n",tot[i],ans[i]);
	return 0;
}