Codechef2015 May - Chef and Strings (后缀自动机）

用后缀自动机统计出出现1~n次的串的数量f[i]

对于ans[k]=sigma（f[i]*C(i,k)) i>=k

 const maxn=;
       mo=;
 var    a,f,rig:array[..maxn] of dword;
     nt:array[..maxn,'a'..'z'] of longint;
     last,sum,i:dword;
     s:ansistring;
     eg:array[..maxn*] of record nt,v:dword; end;
     lt:array[..maxn] of dword;
     el:dword;

     time:array[..maxn] of qword;
     T,j,TT:dword;
     ans:array[..maxn] of qword;
     C:array[-..,-..] of qword;
     du,g:array[..maxn] of longint;
     b:array[..] of longint;
 procedure SAM_init; inline;
 begin
     fillchar(f,sizeof(f),);
     fillchar(nt,sizeof(nt),);
     fillchar(a,sizeof(a),);
     fillchar(rig,sizeof(rig),);
     el:=;
     fillchar(lt,sizeof(lt),);
     fillchar(ans,sizeof(ans),);
     fillchar(du,sizeof(du),);
     fillchar(g,sizeof(g),);
     last:=; sum:=;
 end;

 procedure SAM_ins(ch:char); inline;
 var next,p,np,q,nq:longint;
 begin
     inc(sum); p:=last; np:=sum; a[np]:=a[p]+; last:=np;  rig[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 SAM_visit1; inline;
 var i,l,r:longint;
     c:char;
 begin
     for i:= to sum do
         for c:='a' to 'z' do
             if nt[i][c]<>- then inc(du[nt[i][c]]);

     l:=; r:=; b[]:=; g[]:=;
     while l<=r do
     begin
         for c:='a' to 'z' do
             if nt[b[l]][c]<>- then
             begin
                 dec(du[nt[b[l]][c]]);
                 inc(g[nt[b[l]][c]],g[b[l]]);
                 if du[nt[b[l]][c]]= then
                 begin
                     inc(r);
                     b[r]:=nt[b[l]][c];
                 end;
             end;
         inc(l);
     end;
     for i:= to sum do inc(time[rig[i]],g[i]);
 end;
 procedure dfs(u:dword);
 var i:dword;
 begin
     i:=lt[u];
     while i<> do
     begin
         dfs(eg[i].v);
         rig[u]:=rig[u]+rig[eg[i].v];
         i:=eg[i].nt;
     end;
 end;
 procedure add(u,v:dword); inline;
 begin
     inc(el);
     eg[el].v:=v;
     eg[el].nt:=lt[u];
     lt[u]:=el;
 end;
 procedure SAM_rig; inline;
 begin
     el:=;
     fillchar(lt,sizeof(lt),);
     for i:= to sum do add(f[i],i);
     dfs();
 end;
 procedure main; inline;
 var n,q,i,j:dword;
     cnt:qword;
 begin
     if T<> then
     begin
         fillchar(time,sizeof(time),);
         SAM_init;
     end;
     readln(n,q);
     readln(s);
     SAM_init;
     for i:= to n do SAM_ins(s[i]);
     SAM_rig;
     SAM_visit1;
     for i:= to n do
         for j:=i to n do ans[i]:=(ans[i]+C[j,i]*time[j]) mod mo;
     for i:= to q do
     begin
         readln(j);
         if j>n then writeln() else
         writeln(ans[j]);
     end;
 end;
 begin
     C[,]:=;
     for i:= to  do
         for j:= to i do
         begin
             C[i,j]:=(c[i-,j-]+c[i-,j]);
             if C[i,j]>=mo then C[i,j]:=C[i,j]-mo;
         end;
     readln(T);
     for TT:= to T do main;
 end.