#include using namespace std; const int N = 5000010; int a[N]; void quick_sort(int q[], int l, int r, int k) { if (l >= r)return; int i = l - 1, j = r + 1, x = q[(l + r) >> 1]; while (i < j) { do i++; while (q[i] < x); do j--; while (q[j] > x); if (i < j)swap(q[i], q[j]); } int sl = j - l + 1; if (k <= sl) quick_sort(q, l, j, k);//左半部分搜索 else quick_sort(q, j + 1, r, k - sl);//右半部分搜索 } int main() { //优化输入 ios::sync_with_stdio(false); int n, k; cin >> n >> k; for (int i = 0; i < n; i++)cin >> a[i]; quick_sort(a, 0, n - 1, k); printf("%d", a[k]); return 0; }