POJ 2823(双端队列）

这题考双端队列……好偏门的数据结构……

Program c;const    maxn=1000000;type   node=record        num,d:longint;        end;   douq=record        d:array[1..maxn] of node;        l,r:longint;        end;var   n,k,i,j:longint;   a:array[1..maxn] of longint;   ans1,ans2:array[1..maxn] of longint;   minq,maxq:douq;procedure push(var q:douq;num2,d2:longint);begin   with q do   begin      inc(r);      d[q.r].num:=num2;      d[q.r].d:=d2;   end;end;procedure popl(var q:douq;i:longint);begin   with q do   begin      if d[l].num=i then inc(l);   end;end;procedure popr(up,i:longint);var   j:longint;begin   if up=1 then   begin      with minq do      begin         while (l<r) and (d[r].d>i) do dec(r);         if l=r then         if d[r].d>i then dec(r);      end;   end   else   begin      with maxq do      begin         while (l<r) and (d[r].d<i) do dec(r);         if l=r then         if d[r].d<i then dec(r);      end;   end;end;begin   read(n,k);   for i:=1 to n do read(a[i]);   fillchar(minq,sizeof(minq),0);   minq.l:=1;   fillchar(maxq,sizeof(maxq),0);   maxq.l:=1;   if k=1 then   begin      for i:=1 to n-1 do write(a[i],' ');      writeln(a[n]);      for i:=1 to n-1 do write(a[i],' ');      writeln(a[n]);   end   else   begin      for i:=1 to k do      begin         popr(1,a[i]);         push(minq,i,a[i]);         popr(0,a[i]);         push(maxq,i,a[i]);      end;      ans1[1]:=minq.d[minq.l].d;      ans2[1]:=maxq.d[maxq.l].d;      for i:=k+1 to n do      begin         popl(minq,i-k);         popl(maxq,i-k);         popr(1,a[i]);         push(minq,i,a[i]);         popr(0,a[i]);         push(maxq,i,a[i]);         ans1[i-k+1]:=minq.d[minq.l].d;         ans2[i-k+1]:=maxq.d[maxq.l].d;      end;      for i:=1 to n-k do write(ans1[i],' ');      writeln(ans1[n-k+1]);      for i:=1 to n-k do write(ans2[i],' ');      writeln(ans2[n-k+1]);   end;end.