#include <bits/stdc++.h>
#define ll long long
using namespace std;

ll n, k;
ll a[5000050];

int main() {
	cin >> n >> k;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	sort(a + 1, a + n + 1);
	cout << a[k + 1];
}

60分$↑$

#include <bits/stdc++.h>
#define ll long long
using namespace std;

ll n, k;
ll a[5000050];

int main() {
	scanf("%d%d", &n, &k);
	for (int i = 0; i < n; i++) {
		scanf("%d", &a[i]);
	}
	sort(a, a + n );
	printf("%d", a[k]);
}

AC$↑$

结论：需要格式化输入输出