POJ 2778 DNA Sequence (ac automata, matrix multiplication)

Test instructions: Given n a pattern string that cannot occur, given a length of M, the number of valid strings of length m is required.

Idea: Using AC automata, using the nodes on AC automata to do matrix multiplication.

1#include <iostream>2#include <cstdio>3#include <cstring>4#include <cmath>5#include <string>6#include <algorithm>7#include <queue>8 #defineMOD 1000009 Chars[2005];Ten intChCharx) { One     if(x=='A')return 0; A     if(x=='C')return 1; -     if(x=='G')return 2; -     if(x=='T')return 3; the     return-1; - } - structtrie{ -     intfail[1005],next[1005][5],end[1005],l,root; +     intNewNode () { -          for(intI=0;i<4; i++) +next[l][i]=-1; Aend[l++]=-1; at         returnL-1;  -     } -     voidClear () { -L=0; -root=NewNode (); -     } in     voidInsertChars[]) { -         intLen=strlen (s), now=Root; to          for(intI=0; i<len;i++){ +             if(Next[now][ch (s[i])]==-1) Next[now][ch (S[i])]=NewNode (); -now=next[now][ch (S[i]); the         } *end[now]=1; $     }Panax Notoginseng     voidbuild () { -std::queue<int>Q; the         intNow ; +          for(intI=0;i<4; i++) A          if(next[root][i]==-1) thenext[root][i]=Root; +          Else{ -fail[next[root][i]]=Root; $ Q.push (Next[root][i]); $          }  -          while(!Q.empty ()) { -now=Q.front (); Q.pop (); the             if(end[fail[now]]==1) end[now]=1; -              for(intI=0;i<4; i++){Wuyi                 if(next[now][i]==-1) next[now][i]=Next[fail[now]][i]; the                 Else{ -fail[next[now][i]]=Next[fail[now]][i]; Wu Q.push (Next[now][i]); -                 } About             } $         }  -     } - }ac; - structmatrix{ A     intn,mx[ the][ the]; + Matrix () {} theMatrix (intx) { -n=x; $          for(intI=0; i<n;i++) the           for(intj=0; j<n;j++) themx[i][j]=0; the     }     the }; -Matrixoperator*(Matrix A,matrix b) { in     intn=A.N; theMatrix c=Matrix (n); the      for(intI=0; i<n;i++) About       for(intj=0; j<n;j++) the        for(intk=0; k<n;k++){ the           intTmp= (Long Long) a.mx[i][k]*b.mx[k][j]%MOD; thec.mx[i][j]= (c.mx[i][j]+tmp)%MOD; +       } -     returnC;  the } BayiMatrix powm (Matrix T,intm) { theMatrix r=Matrix (T.N); the      for(intI=0; i<=t.n;i++) -r.mx[i][i]=1; -      while(m) { the         if(m%2) r=r*T; thet=t*T; theM/=2; the     } -     returnR; the } the intMain () { the     intm;94     intN; the      while(SCANF ("%d%d", &n,&m)! =EOF) { the ac.clear (); the          for(intI=0; i<n;i++){98scanf"%s", s); About Ac.insert (s); -         }101 ac.build ();102Matrix a=Matrix (AC. L);103          for(intI=0; I<ac. l;i++)104            for(intj=0;j<4; j + +) the             if(ac.end[ac.next[i][j]]==-1)106a.mx[i][ac.next[i][j]]++;107A=powm (a,m);108         intans=0;109          for(intI=0; i<a.n;i++) theAns= (ans+a.mx[0][i])%MOD;111printf"%d\n", ans);  the     }113}

POJ 2778 DNA Sequence (ac automata, matrix multiplication)