Submission #1235540

#	Time	Username	Problem	Language	Result	Execution time	Memory
1235540		antromancap	Watching (JOI13_watching)	C++20	100 / 100	129 ms	16132 KiB

watching

#include <bits/stdc++.h>

using namespace std;

template <class T> bool mini(T &x, const T &y) { return y < x ? x = y, 1 : 0; }
template <class T> bool maxi(T &x, const T &y) { return y > x ? x = y, 1 : 0; }

const int N = 2005;
int n, p, q, dp[N][N], f[N], g[N];
long long a[N];

bool ok(int x) {
	for (int i = 1; i <= n; i++) {
		f[i] = upper_bound(a + 1, a + n + 1, a[i] + x - 1) - a;
		g[i] = upper_bound(a + 1, a + n + 1, a[i] + 2 * x - 1) - a;
	}
	f[n + 1] = g[n + 1] = n + 1;

	for (int i = 0; i <= p; i++)
		for (int j = 0; j <= q; j++) {
			dp[i][j] = 1;
			if (i) maxi(dp[i][j], f[dp[i - 1][j]]);
			if (j) maxi(dp[i][j], g[dp[i][j - 1]]);
		}
	return dp[p][q] > n;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	cin >> n >> p >> q;
	for (int i = 1; i <= n; i++) cin >> a[i];
	sort(a + 1, a + n + 1);
	n = unique(a + 1, a + n + 1) - a - 1;
	mini(p, n);
	mini(q, n);

	int l = 1, r = (a[n] + 1) >> 1;
	while (l <= r) {
		int m = (l + r) >> 1;
		if (ok(m)) r = m - 1;
		else l = m + 1;
	}
	cout << l;
}

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50