BZOJ 3238: [Ahoi2013]差异 后缀自动机 树形dp

3238: [Ahoi2013]差异

Time Limit: 20 Sec  Memory Limit: 512 MB
Submit: 3660  Solved: 1655
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Description

Input

一行，一个字符串S

Output

 一行，一个整数，表示所求值

Sample Input

cacao

Sample Output

54

HINT

2<=N<=500000,S由小写英文字母组成

第一次写后缀自动机a~

把串翻过来 parent tree 就是后缀树了

之后就可以树形dp啦

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

写的时候默写了一遍构造过程。。。

英语奇差 不要看 我就存下

/*
p->ST(T) np->ST(Tx)
Right(p)->{L} Right(np)->{L+1}
{p,v1,v2,v3...root} these ancestors of p
{r1,r2...rn} the Right of a v
if trans(vi,x) trans(vi+1,x) must be true

those v do not have trans(v,x) only rn can match x
so add a state from v to np

vp is the first one have had trans(v,x)
it's Right->{r1..rn}
q->trans(vp,x) so the Right of q is {(ri)+1 | without {(rn)+1} in because it's not update before}
we notice that we can't insert (rn)+1 straight
it may cause Max(q) get smaller
so only when Max(q)==Max(vp)+1 we can simply insert it 
else we should create a new node named nq to express it and hold q

so
Max(nq)->Max(vp)+1
Parent(nq)=Parent(q)
Parent(q)=nq
Parent(np)=nq
Right(nq)=Right(q)+{L+1}

*/