oj.uz

Submission #384200

# Submission time Handle Problem Language Result Execution time Memory
384200 2021-03-31T19:05:02 Z aryan12 Watching (JOI13_watching) C++17
100 / 100
 249 ms 32492 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long

const int N = 2010;
int a[N + 20];
int dp[N + 20][N + 20];
int n;

bool Cost(int w, int p, int q) {
	int forP[n + 1], forQ[n + 1];
	for(int i = 0; i <= n; i++) {
		forP[i] = 0;
		forQ[i] = 0;
	}
	int prev = 1;
	for(int i = 1; i <= n; i++) {
		for(int j = prev; j <= n; j++) {
			if(a[j] - a[i] >= w) {
				prev = j;
				break;
			}
			else if(j == n) {
				prev = n + 1;
			}
		}
		forP[i] = prev - 1;
	}
	prev = 1;
	for(int i = 1; i <= n; i++) {
		for(int j = prev; j <= n; j++) {
			if(a[j] - a[i] >= 2 * w) {
				prev = j;
				break;
			}
			else if(j == n) {
				prev = n + 1;
			}
		}
		forQ[i] = prev - 1;
	}
	/*cout << "forP array\n";
	for(int i = 1; i <= n; i++) {
		cout << forP[i] << " ";
	}
	cout << "\n";
	cout << "forQ array\n";
	for(int i = 1; i <= n; i++) {
		cout << forQ[i] << " ";
	}
	cout << "\n";*/
	for(int i = 0; i < N; i++) {
		for(int j = 0; j < N; j++) {
			dp[i][j] = 0;
		}
	}
	for(int i = 1; i <= p; i++) {
		dp[i][0] = (dp[i - 1][0] == n) ? dp[i - 1][0] : forP[dp[i - 1][0] + 1];
	}
	for(int j = 1; j <= q; j++) {
		dp[0][j] = (dp[0][j - 1] == n) ? dp[0][j - 1] : forQ[dp[0][j - 1] + 1];
	}
	for(int i = 1; i <= p; i++) {
		for(int j = 1; j <= q; j++) {
			if(dp[i - 1][j] == n || dp[i][j - 1] == n) {
				dp[i][j] = n;
				continue;
			}
			dp[i][j] = max((forP[dp[i - 1][j] + 1]), (forQ[dp[i][j - 1] + 1]));
		}
	}
	if(dp[p][q] == n)
		return true;
	return false;
}

void Solve() {
	int p, q;
	cin >> n >> p >> q;
	for(int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	sort(a + 1, a + 1 + n);
	if(p + q >= n) {
		cout << "1\n";
		return;
	}
	int left = 1, right = 1e9;
	int mid, ans = 1e9 + 1;
	while(left <= right) {
		//cout << "left = " << left << ", right = " << right << "\n";
		mid = (left + right) / 2;
		//cout << "mid = " << mid << "\n";
		if(Cost(mid, p, q)) {
			//cout << "mid is coming true\n";
			right = mid - 1;
			ans = mid;
		}
		else {
			//cout << "mid is coming false\n";
			left = mid + 1;
		}
	}
	cout << ans << "\n";
}

int32_t main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	Solve();
	return 0;
}

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 142 ms 32364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 142 ms 32364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 2 ms 364 KB Output is correct
7 Correct 144 ms 32236 KB Output is correct
8 Correct 141 ms 32236 KB Output is correct
9 Correct 140 ms 32236 KB Output is correct
10 Correct 137 ms 32336 KB Output is correct
11 Correct 140 ms 32236 KB Output is correct
12 Correct 148 ms 32364 KB Output is correct
13 Correct 142 ms 32336 KB Output is correct
14 Correct 135 ms 32236 KB Output is correct
15 Correct 136 ms 32236 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 147 ms 32492 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 2 ms 364 KB Output is correct
6 Correct 2 ms 364 KB Output is correct
7 Correct 147 ms 32364 KB Output is correct
8 Correct 154 ms 32448 KB Output is correct
9 Correct 163 ms 32492 KB Output is correct
10 Correct 179 ms 32400 KB Output is correct
11 Correct 159 ms 32364 KB Output is correct
12 Correct 249 ms 32364 KB Output is correct
13 Correct 143 ms 32364 KB Output is correct
14 Correct 142 ms 32364 KB Output is correct
15 Correct 149 ms 32364 KB Output is correct