Cod sursa(job #477114)

Utilizator 05_YohnE1 La5c01 05_Yohn Data 13 august 2010 15:13:55
Problema Statistici de ordine Scor 50
Compilator fpc Status done
Runda Arhiva educationala Marime 0.97 kb
var a:array[1..3000000]of longint;
buf:array[0..10241024]of byte;
n,k,i:longint;

function partition(p,q:longint):longint;
var x,i,j,aux:longint;
begin
x:=a[p];
i:=p;
for j:=p+1 to q do
    if a[j]<=x then begin
       i:=i+1;
       aux:=a[i];
       a[i]:=a[j];
       a[j]:=aux;
       end;
aux:=a[p]; a[p]:=a[i]; a[i]:=aux;
partition:=i;
end;

function RandSel(p,q,i:longint):longint;
var r,k:longint;
begin
if p=q then RandSel:=a[p]
       else begin
            r:=partition(p,q);
            k:=r-p+1;
            if k=i then RandSel:=a[r]
                   else begin
                        if i<k then RandSel:=RandSel(p,r-1,i)
                               else RandSel:=RandSel(r+1,q,i-k);
                        end;
            end;
end;


begin
assign(input,'sdo.in');
reset(input);
settextbuf(input,buf);
assign(output,'sdo.out');
rewrite(output);
read(n,k);
for i:=1 to n do read(a[i]);
write(RandSel(1,n,k));
close(output);
end.