nlogn的最长不下降子序列【tyvj1254挑选士兵】

 var
   a,d:Array[-..]of longint;
   i,n,m,k,l:longint;
 function erfen(x:longint):longint;
   var mid,h,t:longint;
   begin
   h:=;t:=l;
   erfen:=;
   while h<=t do
     begin
     mid:=(h+t)shr ;
     if d[mid]<=x then
       begin erfen:=mid;h:=mid+;end
     else
       t:=mid-;
     end;
   end;

 begin
   readln(n);
   for i:= to n do
     read(a[i]);
   d[]:=-maxlongint; l:=;
   for i:= to n do
     if a[i]>=d[l] then
       begin
       inc(l);
       d[l]:=a[i];
       end
     else
       begin
       k:=erfen(a[i]);
       if a[i]<d[k+] then d[k+]:=a[i];
       end;
   writeln(l);
   end.