Submission #264753

#	Time	Username	Problem	Language	Result	Execution time	Memory
264753		Atalasion	Watching (JOI13_watching)	C++14	100 / 100	207 ms	32124 KiB

watching

//khodaya khodet komak kon
#include <bits/stdc++.h>

#define F first
#define S second
#define pb push_back
#define all(x) x.begin(), x.end()
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
#define int long long

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

const int N = 2000 + 10;
const ll MOD = 1000000000 + 7;
const ll INF = 1000000000000000010;
const ll LOG = 25;

int dp[N][N], n, p, q, a[N], nxt[N], nxt2[N];

bool isval(int w){
	//cout << w << ' ';
	memset(dp, 0, sizeof dp);
	memset(nxt, 0, sizeof nxt);
	memset(nxt2, 0, sizeof nxt2);
	int pnt = 1, pnt2 = 1;
	for (int i = 1; i <= n - 1; i++){
		while (a[pnt + 1] - a[i] <= w - 1) pnt++;
		while (a[pnt2 + 1] - a[i] <= 2 * w - 1) pnt2++;
		nxt[i] = pnt;
		nxt2[i] = pnt2;
	}
	for (int i = 0; i <= p; i++) for (int j = 0; j <= q; j++){
		int x = dp[i][j];
		//cout << i << ' ' << j << ' ' << dp[i][j] << '\n';
		x++;
		if (dp[i][j] >= n - 1) return 1;
		dp[i + 1][j] = max(dp[i + 1][j], nxt[x]);
		dp[i][j + 1] = max(dp[i][j + 1], nxt2[x]);
	}
//	cout << dp[p][q] << '\n';
	return (dp[p][q] >= n - 1);
}

int32_t main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin >> n >> p >> q;
	for (int i = 1; i <= n; i++) cin >> a[i];
	sort(a + 1, a + n + 1);
	n++;
	a[n] = INF;
	int l = 0, r = 1000000000;
	while (r - l > 1){
		int md = (l + r) >> 1;
		if (isval(md)) r = md;
		else l = md;
	}
	cout << r;
//	isval(32);
	return 0;
}

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