是这样做的

program robertbear;

var

a,c,ls,num:array[1..500001] of longint;

i,j,k,m,n,t,max:longint;

total:qword;

ave,mid:real;

flag:boolean;

procedure Q(l,r:longint);

var

i,j,k,m:longint;

begin

i:=l;

j:=r;

k:=a[(i+l) div 2];

while i