Cod sursa(job #373225)

Utilizator Bogdan_tmmTirca Bogdan Bogdan_tmm Data 13 decembrie 2009 00:44:15
Problema Statistici de ordine Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.75 kb
#include<fstream>
#include<algorithm>
#include<ctime>
#include<cstdlib>
using namespace std;
const int Max=3000003;
int a[Max];
int n,k;
ifstream fin ("sdo.in");
ofstream fout ("sdo.out");
int partition(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 st,int dr,int ind)
{
	if(st==dr)
		return ;
	int q=partition(st,dr);
	int k=q-st+1;
	if(ind<=k)
		sdo(st,q,ind);
	else
		sdo(q+1,dr,ind-k);
}
int main()
{
	srand(time(NULL));
	fin>>n>>k;
	for(int i=1;i<=n;i++)
	{
		fin>>a[i];
	}
	sdo(1,n,k);
	fout<<a[k]<<'\n';
	return 0;
}