ac1161.pas

某牛人写的acm.tongji.edu.cn上大部分ac的代码,仅供学习研究,请不要用来作弊

program tju1161;
const
  maxn=10000;
var
  a:array[1..maxn]of longint;
  n,i:longint;
  sl,sr,ans:int64;
procedure qsort(s,t:word);
  var
    p,i,j,tmp:longint;
  begin
    if s>=t then exit;
    p:=s+random(t-s+1);
    tmp:=a[p];a[p]:=a[s];
    i:=s;j:=t;
    repeat
      while (i<j) and (a[j]>=tmp) do dec(j);
      if i=j then break;a[i]:=a[j];inc(i);
      while (i<j) and (a[i]<=tmp) do inc(i);
      if i=j then break;a[j]:=a[i];dec(j);
    until i=j;
    a[i]:=tmp;
    qsort(s,i-1);
    qsort(i+1,t);
  end;
begin
  repeat
    read(n);sl:=0;sr:=0;ans:=0;
    for i:=1 to n do begin
      read(a[i]);inc(sr,a[i]);
    end;
    qsort(1,n);
    for i:=1 to n do begin
      inc(sl,a[i]);dec(sr,a[i]);
      inc(ans,sr-sl+int64(a[i])*(i*2-n));
    end;
    writeln(ans);
  until seekeof;
end.