Pagini recente » Cod sursa (job #1489286) | Cod sursa (job #2811372) | Cod sursa (job #1017849) | Cod sursa (job #1913566) | Cod sursa (job #2610450)
#include <iostream>
#include <fstream>
#include <random>
#include <ctime>
using namespace std;
ifstream f("sdo.in");
ofstream g ("sdo.out");
int v[3000005], n, k;
int pivot_rand(int st, int dr)
{
if(st<dr)
{
if(dr-1==st)
{
if(v[st]>v[dr])
std::swap(v[st], v[dr]);
return st;
}
srand((int)time(0));
int r=(rand()%(st-dr+1)+st);
int p=v[r];
std::swap(v[r], v[dr]);
int i=st-1;
for(int j=st; j<=dr-1; j++)
{
if(v[j]<p)
{
i++;
std::swap(v[i], v[j]);
}
}
std::swap(v[i+1], v[dr]);
return i+1;
}
}
void quicksort_rand(int st, int dr, int& val)
{
if(st<dr)
{
int p=pivot_rand(st, dr);
if(p==k) {val=v[p]; return;}
if(k<p && st!=p-1)quicksort_rand(st, p-1, val);
if(k>p && p+1!=dr)quicksort_rand(p+1, dr, val);
}
}
int main()
{
f>>n;
f>>k;
for(int i=1; i<=n; i++)
f>>v[i];
int val;
quicksort_rand(1, n, val);
g<<val;
return 0;
}