Cod sursa(job #373223)

Utilizator Bogdan_tmmTirca Bogdan Bogdan_tmm Data 13 decembrie 2009 00:40:23
Problema Statistici de ordine Scor 60
Compilator cpp Status done
Runda Arhiva educationala Marime 0.8 kb
#include<stdio.h>
#include<algorithm>
#include<ctime>
#include<cstdlib>
using namespace std;
const int Max=3000003;
int a[Max];
int n,k;
int partition(int a[Max],int st,int dr)
{
	int i=st-1,j=dr+1,q=a[st+(rand()%(dr-st+1))];
	while(1)
	{
		do
		{
			i++;
		}while(a[i]<q);
		do
		{
			j--;
		}while(q<a[j]);
		if(i<j)
			swap(a[i],a[j]);
		else
			return j;
	}
	return 0;
}
inline void sdo(int a[Max],int st,int dr,int ind)
{
	if(st==dr)
		return ;
	int q=partition(a,st,dr);
	int k=q-st+1;
	if(ind<=k)
		sdo(a,st,q,ind);
	else
		sdo(a,q+1,dr,ind-k);
}
int main()
{
	srand(time(NULL));
	freopen("sdo.in","r",stdin);
	freopen("sdo.out","w",stdout);
	scanf("%d%d",&n,&k);
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&a[i]);
	}
	sdo(a,1,n,k);
	printf("%d\n",a[k]);
	return 0;
}