为什么有两个点过不去

var s,i,n:longint;a,b:array[1..1000]of longint;
procedure sort(l,r: longint);
      var
         i,j,x,y: longint;
      begin
         i:=l;
         j:=r;
         x:=a[(l+r) div 2];
         repeat
           while a[i]<x do
            inc(i);
           while x<a[j] do
            dec(j);
           if not(i>j) then
             begin
                y:=a[i];
                a[i]:=a[j];
                a[j]:=y;
                 y:=b[i];
                b[i]:=b[j];
                b[j]:=y;
                inc(i);
                j:=j-1;
             end;
         until i>j;
         if l<j then
           sort(l,j);
         if i<r then
           sort(i,r);
      end;
begin
  readln(n);
  for i:=1 to n do begin read(a[i]);b[i]:=i;end;
  sort(1,n);
  for i:=1 to n do write(b[i],' ');
  writeln;
  for i:=1 to n do
  s:=s+a[i]*(n-i);
  writeln(s/n:0:2);
end.