Submission #1216365

#	Time	Username	Problem	Language	Result	Execution time	Memory
1216365		trimkus	Let's Win the Election (JOI22_ho_t3)	C++20	61 / 100	2595 ms	4424 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
ld dp[2][501][501];

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	int n, k;
	cin >> n >> k;
	//~ cerr << "A\n";
	vector<array<ld, 2>> a(n);
	int cnt = 0;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < 2; ++j) {
			cin >> a[i][j];	
		}
		cnt += (a[i][1] != -1);
		swap(a[i][0], a[i][1]);
	}
	sort(begin(a), end(a));
	auto chmin = [&](ld& x, ld y) -> void {
		x = min(x, y);
	};
	//~ cerr << "a\n";
	int left = 0, right = min(k, cnt) - 1;
	int res = min(k, cnt);
	auto calc = [&](int take) -> ld {
		for (int i = 0; i < 2; ++i) {
			for (int j = 0; j <= k - take; ++j) {
				for (int z = 0; z <= take; ++z) {
					dp[i][j][z] = 1e18;
				}
			}
		}
		dp[0][0][0] = 0;
		for (int j = 0; j < n; ++j) {
			int p = j & 1;
			for (int l = 0; l <= k - take; ++l) {
				for (int z = 0; z <= take; ++z) {
					dp[p ^ 1][l][z] = dp[p][l][z];
					if (l > 0) {
						chmin(dp[p ^ 1][l][z], dp[p][l - 1][z] + a[j][1] / (take + 1));
					}
					if (a[j][0] != -1 && z > 0) {
						chmin(dp[p ^ 1][l][z], dp[p][l][z - 1] + a[j][0] / z);
					}
				}
			}
		}
		//~ cerr << take << " = " << dp[n & 1][k][take] << "\n";
		return dp[n & 1][k - take][take];
	};
	while (left <= right) {
		int m = (left + right) / 2;
		if (calc(m) <= calc(m + 1)) {
			right = m - 1;
			res = m;
		} else {
			left = m + 1;
		}
	}
	cout << fixed << setprecision(3) << calc(res) << "\n";
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 5
• Subtask 3: 11 / 11
• Subtask 4: 12 / 12
• Subtask 5: 33 / 33
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23