BZOJ1030 [JSOI2007] text generator (AC automaton +DP)

The main idea: to find the length of $m$ in a string consisting of $ ' A '-' Z ' $ contains at least one of the number of n pattern strings given.

Portal

It seems that the non-nude AC automata topics are all running on the machine DP ...

The direct solution is not good, we can use $26^m$ minus the number of pattern strings.

Build the automaton, set f[i][j] means walk I step, now in the J number of the path of the node.

Then F[i][j] can be transferred f[i+1][son[j][k]].
Is the state of i+1 characters K.
Finally put all F[m][i] tired and is not readable string.

This is the online argument, presumably that is the meaning.

I wrote the pointer version of the trie, ugly, look at the above explanation is good.

1#include <cstring>2#include <cstdio>3#include <cmath>4#include <algorithm>5 #defineForu (i,x,y) for (int i=x;i<=y;i++)6 using namespacestd;7 Const intMod=10007;8 structtrie{9     intv,f[201];TenTrie *nxt[ -],*fail; One     voidInit () {v=0; Fail=null;foru (I,0, -) Nxt[i]=null;memset (F,0,sizeof(f)); A}*r,*q[10000],*ind[10000]; -  - intn,m,ans,ans2,cnt; the Charch[ $]; -  - voidAddChar*s) { -Trie *k=r,*p; +     intL=strlen (s); -Foru (I,0, L-1){ +         intid=s[i]-'A'; A         if(!k->Nxt[id]) { atp= (trie*)malloc(sizeof(Trie)); -P->init (); -k->nxt[id]=p; -k=p; -ind[++cnt]=p; -}Else{ inK=k->Nxt[id]; -         } to     } +k->v=1; - } the  * voidSetfail () { $Trie *k=r,*p;Panax Notoginseng     ints=1, t=0; -q[++t]=R; the      while(s<=t) { +k=q[s++]; AForu (I,0, -){ the             if(k->Nxt[i]) { +P=k->fail; -                  while(P&&!p->nxt[i]) p=p->fail; $K->nxt[i]->fail= (p?p->nxt[i]:r); $Q[++t]=k->Nxt[i]; -}Else -K->nxt[i]= (k!=r?k->fail->nxt[i]:r); the         } -         if(k!=r) k->v|=k->fail->v;//if the suffix of a string can be understood, then the string can be understood.Wuyi     } the } -  Wu voidWork () { -r->f[0]=1; AboutForu (I,1, M) { $Foru (J,0, CNT) { -             if(IND[J]-&GT;V)Continue; -Foru (k,0, -){ -ind[j]->nxt[k]->f[i]+=ind[j]->f[i-1]; Aind[j]->nxt[k]->f[i]%=MoD; +             } the         } -     } $Foru (I,0, CNT) the         if(!ind[i]->v) { theAns2+=ind[i]->F[m]; theans2%=MoD; the         } -ans=1; inForu (I,1, m) ans= (ans* -)%MoD; theprintf"%d\n", ((ans-ans2)%mod+mod)%MoD); the } About  the intMain () { theR= (trie*)malloc(sizeof(Trie)); theR->init (); +ind[0]=R; -scanf"%d%d",&n,&m); theForu (I,1nn) {Bayiscanf"%s", ch); the Add (CH); the     } - Setfail (); - Work (); the     return 0; the}

BZOJ1030 [JSOI2007] text generator (AC automaton +DP)