KStat

#include <iostream>
#include <vector>

int partition(std::vector<int>& v, int l, int r) {
  if (r - l <= 1) return l;
  std::swap(v[r - 1], v[(r + l) / 2]);
  int i = l;
  const int& x = v[r - 1];
  for (int j = l; j < r - 1; ++j) {
    if (v[j] < x) {
      std::swap(v[i], v[j]);
      ++i;
    }
  }
  std::swap(v[i], v[r - 1]);
  return i;
}

int KStat(std::vector<int>& v, int k) {
  int l = 0, r = v.size();
  while (true) {
    const int p = partition(v, l, r);
    if (p == k) return v[k];
    if (p > k) {
      r = p;
    } else {
      l = p + 1;
    }
  }
}

int main() {
  int n = 0, k = 0;
  std::cin >> n >> k;
  std::vector<int> v(n, 0);
  for (int i = 0; i < n; ++i) {
    std::cin >> v[i];
  }
  std::cout << KStat(v, k);
  return 0;
}