算法模板——AC自动机

实现功能——输入N，M，提供一个共计N个单词的词典，然后在最后输入的M个字符串中进行多串匹配（关于AC自动机算法，此处不再赘述，详见：Aho-Corasick 多模式匹配算法、AC自动机详解。考虑到有时候字典会相当稀疏，所以引入了chi和bro指针进行优化——其原理比较类似于邻接表，这个东西和next数组本质上是一致的，只是chi和bro用于遍历某一节点下的子节点，next用于查询某节点下是否有需要的子节点）

 type
     point=^node;
     node=record
                ex:longint;st:ansistring;
                ct:char;
                fat,jump,chi,bro:point;
                next:array['A'..'Z'] of point;
     end;
 var
    i,j,k,l,m,n:longint;
    head,p:point;
    s1,s2:ansistring;
 function getpoint:point;inline;
          var p:point;c1:char;
          begin
               new(p);
               p^.ex:=;p^.st:='';
               p^.ct:=chr();
               p^.bro:=nil;p^.chi:=nil;
               p^.fat:=nil;p^.jump:=head;
               for c1:='A' to 'Z' do p^.next[c1]:=nil;
               exit(p);
          end;
 procedure ins(s1:ansistring;x:longint);inline;
           var p:point;s2:ansistring;i:longint;
           begin
                p:=head;S2:='';
                for i:= to length(s1) do
                    begin
                         s2:=s2+s1[i];
                         if p^.next[s1[i]]=nil then
                            begin
                                 p^.next[s1[i]]:=getpoint;
                                 p^.next[s1[i]]^.fat:=p;
                                 p^.next[s1[i]]^.st:=s2;
                                 p^.next[s1[i]]^.ct:=s1[i];
                                 p^.next[s1[i]]^.bro:=p^.chi;
                                 p^.chi:=p^.next[s1[i]];
                            end;
                         p:=p^.next[s1[i]];
                    end;
                if p^.ex= then p^.ex:=x;
           end;
 procedure linkit;inline;
           var i,j,k,l,f,r:longint;
               d:array[..] of point;
               p,p1,p2:point;
           begin
                f:=;r:=;d[]:=head;
                while f<r do
                      begin
                           p:=d[f]^.chi;
                           while p<>nil do
                                 begin
                                      d[r]:=p;
                                      if d[f]<>head then
                                         begin
                                              p1:=d[f]^.jump;
                                              while p1<>head do
                                                    begin
                                                         if p1^.next[p^.ct]<>nil then break;
                                                         p1:=p1^.jump;
                                                    end;
                                              if p1^.next[p^.ct]<>nil then p^.jump:=p1^.next[p^.ct];
                                         end;
                                      inc(r);
                                      p:=p^.bro;
                                 end;
                           inc(f);
                      end;
           end;
 procedure fit(s1:ansistring);inline;
           var p,p1:point;i:longint;
           begin
                p:=head;
                for i:= to length(s1) do
                    begin
                         if p^.next[s1[i]]=nil then
                            begin
                                 while (p^.next[s1[i]]=nil) and (p<>head) do p:=p^.jump;
                                 if p^.next[s1[i]]<>nil then p:=p^.next[s1[i]];
                            end
                         else p:=p^.next[s1[i]];
                         p1:=p;
                         while p1<>head do
                               begin
                                    if p1^.ex<> then writeln('No.',p1^.ex,' ',p1^.st,' From:',i-length(p1^.st)+);
                                    p1:=p1^.jump;
                               end;
                    end;
           end;
 begin
      readln(n,m);
      head:=getpoint;head^.jump:=head;
      for i:= to n do
          begin
               readln(s1);
               ins(upcase(s1),i);
          end;
      linkit;
      for i:= to m do
          begin
               readln(s1);
               fit(upcase(s1));
          end;
 end.