Submission #264582

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
264582	2020-08-14T07:52:05 Z	ruler	Watching (JOI13_watching)	C++14	100 / 100	259 ms	16256 KB

watching

// IOI 2021
#include <bits/stdc++.h>
using namespace std;

#define endl '\n'
#define ends ' '
#define endt '\t'
#define die(x) return cout << x << endl, 0
#define all(v) v.begin(), v.end()
#define sz(x) (int)(x.size())
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) { cerr << ends << H; debug_out(T...); }
#define debug(...) cerr << "{" << #__VA_ARGS__ << "}:", debug_out(__VA_ARGS__)
typedef long long ll;
typedef pair<int, int> pii;
const int INF = 1e9;
const ll MOD = 1e9 + 7;

////////////////////////////////////////////////////////////////////
 
const int N = 2e3 + 5;

int n, p, q, A[N], DP[N][N], P[N], Q[N];

bool IsVal(int w) {
	P[0] = Q[0] = 0;
	for (int i = 0; i < n; i++) {
		if (i) P[i] = P[i - 1];
		while (P[i] < n && A[i] + w - 1 >= A[P[i]]) P[i]++;
	}
	for (int i = 0; i < n; i++) {
		if (i) Q[i] = Q[i - 1];
		while (Q[i] < n && A[i] + w + w - 1 >= A[Q[i]]) Q[i]++;
	}
	P[n] = Q[n] = n;
	memset(DP, 0, sizeof DP);
	for (int i = 0; i <= p; i++) for (int j = 0; j <= q; j++) {
		if (i < p) DP[i + 1][j] = max(DP[i + 1][j], P[DP[i][j]]);
		if (j < q) DP[i][j + 1] = max(DP[i][j + 1], Q[DP[i][j]]);
	}
	return DP[p][q] == n;
}

int main() {
 
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	mt19937 Rnd(time(0));

	cin >> n >> p >> q;
	for (int i = 0; i < n; i++) cin >> A[i];
	sort(A, A + n);
	if (p + q >= n) die(1);
	int dw = 0, up = INF + 1;
	while (up - dw > 1) {
		int md = (dw + up) >> 1;
		if (IsVal(md)) up = md;
		else dw = md;
	}
	cout << up << endl;

	return 0;
}

Subtask #1

50.0 / 50.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	76 ms	16128 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	71 ms	16128 KB	Output is correct
4	Correct	1 ms	384 KB	Output is correct
5	Correct	1 ms	384 KB	Output is correct
6	Correct	1 ms	384 KB	Output is correct
7	Correct	68 ms	16128 KB	Output is correct
8	Correct	71 ms	16128 KB	Output is correct
9	Correct	69 ms	16248 KB	Output is correct
10	Correct	67 ms	16128 KB	Output is correct
11	Correct	70 ms	16128 KB	Output is correct
12	Correct	73 ms	16128 KB	Output is correct
13	Correct	72 ms	16248 KB	Output is correct
14	Correct	70 ms	16248 KB	Output is correct
15	Correct	68 ms	16128 KB	Output is correct

Subtask #2

50.0 / 50.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	75 ms	16160 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	1 ms	384 KB	Output is correct
4	Correct	1 ms	384 KB	Output is correct
5	Correct	1 ms	384 KB	Output is correct
6	Correct	1 ms	384 KB	Output is correct
7	Correct	75 ms	16128 KB	Output is correct
8	Correct	89 ms	16128 KB	Output is correct
9	Correct	96 ms	16128 KB	Output is correct
10	Correct	108 ms	16248 KB	Output is correct
11	Correct	106 ms	16256 KB	Output is correct
12	Correct	259 ms	16156 KB	Output is correct
13	Correct	73 ms	16248 KB	Output is correct
14	Correct	70 ms	16128 KB	Output is correct
15	Correct	75 ms	16252 KB	Output is correct