ac1011.pas

同济大学 Online在线题库 AC源代码合集 程序设计竞赛必看资料

program tju1011;
const
  maxn=24999;
  res:array[1..4,0..3]of byte=((2,6,8,4),(4,2,6,8),(6,8,4,2),(8,4,2,6));
var
  a:array[1..maxn]of longint;
  i,x,five:word;
begin
  a[1]:=1;
  for i:=2 to maxn do begin
    x:=i;
    while x mod 10=0 do x:=x div 10;
    if odd(x) then begin
      five:=0;
      while x mod 5=0 do begin if five=3 then five:=0 else inc(five);x:=x div 5;end;
      a[i]:=res[a[i-1]*x mod 10 shr 1,five];
    end
    else
      a[i]:=a[i-1]*x mod 10;
  end;
  for i:=2 to maxn do
    inc(a[i],a[i-1]);
  repeat
    read(x);
    writeln(a[x]);
  until seekeof;
end.