练 习 题

#include <bits/stdc++.h>
using namespace std;
int p(int a[], int l, int r) {
	int v = a[r];
	int i = l - 1;
	for (int j = l; j < r; j++) {
		if (a[j] >= v) {
			i++;
			swap(a[i], a[j]);
		}
	}
	swap(a[i+1], a[r]);
	return i + 1;
}
int fi(int a[], int l, int r, int k) {
	if (l == r) return a[l];
	int s = p(a, l, r);
	int b = s - l + 1;
	if (b == k) return a[s];
	else if (b > k) return fi(a, l, s-1, k);
	else return fi(a, s+1, r, k-b);
}

int main() {
	int n, k;
	cin >> n >> k;
	int a[100000];
	for (int i = 0; i < n; i++) cin >> a[i];
	cout << fi(a, 0, n-1, k) << endl;
	return 0;
}

#include <bits/stdc++.h>

using namespace std;

int main() {
	int n;
	cin >> n;
	
	int s[1000], e[1000];
	for (int i = 0; i < n; ++i) {
		cin >> s[i] >> e[i];
	}
	
	for (int i = 0; i < n - 1; ++i) {
		for (int j = 0; j < n - i - 1; ++j) {
			if (s[j] > s[j + 1]) {
				swap(s[j], s[j + 1]);
				swap(e[j], e[j + 1]);
			}
		}
	}
	int ms = s[0], me = e[0];
	bool f = true;
	for (int i = 1; i < n; ++i) {
		if (s[i] <= me) {
			me = max(me, e[i]);
		} else {
			f = false;
			break;
		}
	}
	if (f==true) {
		cout << ms << " " << me << endl;
	} else {
		cout << "no" << endl;
	}
	return 0;
}