Submission #485337

#	Time	Username	Problem	Language	Result	Execution time	Memory
485337		zhougz	Watching (JOI13_watching)	C++17	50 / 100	1096 ms	87708 KiB

watching

/**
 *    author: chowgz
 *    created: 06/11/2021 20:19:08
**/
#include <bits/stdc++.h>

using namespace std;

int n, p, q;
const int MAXN = 2'000;
int arr[MAXN + 5];
int m;
map<long long, bool> mmap;

long long hsh(int x, int y, int z) {
	return x * 3'000 * 3'000 + y * 3'000 + z;
}

bool dp(int x, int y, int z) {
	// x: considering arr[x], y: # short pieces left, z: # long pieces left
#ifdef LOCAL
	cerr << "x: " << x << " y: " << y << " z: " << z << endl;
#endif
	if (y < 0 || z < 0) {
		return false;
	}
	if (y + z >= n - x) {
		return true;
	}
	if (mmap.find(hsh(x, y, z)) != mmap.end()) {
		return mmap[hsh(x, y, z)];
	}
	return mmap[hsh(x, y, z)]
		= dp(upper_bound(arr, arr + n, arr[x] + m - 1) - arr, y - 1, z) // use short
		|| dp(upper_bound(arr, arr + n, arr[x] + 2 * m - 1) - arr, y, z - 1);
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n >> p >> q;
	for (int i = 0; i < n; i++) {
		cin >> arr[i];
	}
	if (p + q >= n) {
		cout << 1 << '\n';
		return 0;
	}
	sort(arr, arr + n);
	int l = 1, r = 1'000'000'000;
	while (l != r) {
		m = (l + r) / 2;
		mmap.clear();
		if (dp(0, p, q)) {
			r = m;
		} else {
			l = m + 1;
		}
	}
	cout << l << '\n';
	return 0;
}

• Subtask 1: 50 / 50
• Subtask 2: 0 / 50