ZOJ2006 (后缀自动机）

求一个字符串的最小表示法。

将字符串S倍长，从根走length(s)步所走路径即为最小表示法。

记所到达位置为x，则这个最小表示法的起点为a[x]-len(s)+1

 const maxn=;
 var T:longint;
     nt:array[..maxn,'a'..'z'] of longint;
     a,f:array[..maxn] of longint;
     sum,last:longint;
     s:ansistring;
 procedure Sam_init;
 begin
     fillchar(nt,sizeof(nt),);
     fillchar(a,sizeof(a),);
     fillchar(f,sizeof(f),);
     sum:=; last:=;
 end;
 procedure Sam_ins(i:longint);
 var p,q,np,nq:longint;
     ch:char;
 begin
     ch:=s[i];
     p:=last; inc(sum); np:=sum; a[np]:=a[p]+; last:=np;
     while (p<>-) and (nt[p][ch]=-) do begin nt[p][ch]:=np; p:=f[p]; end;
     if p=- then f[np]:= else
     begin
         q:=nt[p][ch];
         if a[p]+=a[q] then f[np]:=q else
         begin
             inc(sum); nq:=sum; a[nq]:=a[p]+;
             nt[nq]:=nt[q]; f[nq]:=f[q];
             f[q]:=nq; f[np]:=nq;
             while (p<>-) and (nt[p][ch]=q) do begin nt[p][ch]:=nq; p:=f[p]; end;
         end;
     end;
 end;
 procedure dfs(now,len:longint);
 var ch:char;
 begin
     if len= then
     begin
         writeln(a[now]-length(s) div +);
         exit;
     end;
     for ch:='a' to 'z' do
         if nt[now][ch]<>- then
         begin
             dfs(nt[now][ch],len-);
             exit;
         end;
 end;
 procedure main;
 var i:longint;
 begin
     readln(s);
     s:=s+s;
     Sam_init;
     for i:= to length(s) do Sam_ins(i);
     dfs(,length(s) div );
 end;
 begin
     readln(T);
     while T> do begin dec(T); main; end;
 end.