oj.uz

Submission #1106572

# Submission time Handle Problem Language Result Execution time Memory
1106572 2024-10-30T16:41:14 Z xnqs Watching (JOI13_watching) C++17
50 / 100
 1000 ms 8472 KB 
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <cstring>

int x, p, q;
std::vector<int> arr;
std::vector<int> next[2];
std::pair<int,int> dp[2000][510];

std::pair<int,int> solve(int pos, int k, int lambda) {
	if (pos==x) {
		return {0, 0};
	}
	if (dp[pos][k].first!=-1) {
		return dp[pos][k];
	}

	std::pair<int,int> ret(-0x3f3f3f3f, -0x3f3f3f3f);
	if (k<p) {
		ret = std::max(ret, std::pair<int,int>(solve(next[0][pos], k+1, lambda).first + next[0][pos]-pos,
		                                       solve(next[0][pos], k+1, lambda).second));
	}

	ret = std::max(ret, std::pair<int,int>(solve(next[1][pos], k, lambda).first + next[1][pos]-pos - lambda,
	                                       solve(next[1][pos], k, lambda).second + 1));
	return dp[pos][k] = ret;
}

bool can_solve(int cap) {
	bool mode = (p>q);
	for (int i = 0; i < 2; i++) {
		next[i].resize(x);
		for (int l = x-1, r = x-1; l >= 0; l--) {
			while (arr[r]-arr[l]+1>(i+1)*cap) {
				--r;
			}
			next[i][l] = r+1;
		}
	}

	if (mode) {
		std::swap(p,q);
		std::swap(next[0],next[1]);
	}

	const auto bs_lambda = [&]() {
		int ret = -1;
		int l = 0, r = 2000;
		while (l<=r) {
			int m = (l+r)>>1;
			memset(dp,-1,sizeof(dp));
			auto [max, cnt] = solve(0,0,m);
			if (cnt<=q) {
				ret = m;
				l = m+1;
			}
			else {
				r = m-1;
			}
		}
		return ret;
	};

	int lambda = bs_lambda();
	auto [max, cnt] = solve(0,0,lambda);
	if (mode) {
		std::swap(p,q);
		std::swap(next[0],next[1]);
	}
	return (max + cnt*lambda == x);
}

int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(NULL);
	std::cout.tie(NULL);

	std::cin >> x >> p >> q;

	// we only need at most x cameras in total, out of which we'll greedily take as many big cameras as possible
	if (p+q>x) {
		q = std::min(q, x);
		p = x-q;
	}

	for (int i = 0, tmp; i < x; i++) {
		std::cin >> tmp;
		arr.emplace_back(tmp);
	}

	std::sort(arr.begin(),arr.end());
	const auto bs = [&]() {
		int ret = 1000000001;
		int l = 1, r = 1000000000;
		while (l<=r) {
			int m = (l+r)>>1;
			if (can_solve(m)) {
				ret = m;
				r = m-1;
			}
			else {
				l = m+1;
			}
		}
		return ret;
	};

	std::cout << bs() << "\n";
	//can_solve(bs(),1);
}

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 8272 KB Output is correct
2 Correct 41 ms 8272 KB Output is correct
3 Correct 49 ms 8272 KB Output is correct
4 Correct 41 ms 8272 KB Output is correct
5 Correct 38 ms 8448 KB Output is correct
6 Correct 43 ms 8272 KB Output is correct
7 Correct 51 ms 8272 KB Output is correct
8 Correct 48 ms 8272 KB Output is correct
9 Correct 50 ms 8272 KB Output is correct
10 Correct 46 ms 8272 KB Output is correct
11 Correct 46 ms 8272 KB Output is correct
12 Correct 59 ms 8272 KB Output is correct
13 Correct 40 ms 8272 KB Output is correct
14 Correct 39 ms 8272 KB Output is correct
15 Correct 42 ms 8272 KB Output is correct

Subtask #2
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 49 ms 8272 KB Output is correct
2 Correct 49 ms 8448 KB Output is correct
3 Execution timed out 1055 ms 8472 KB Time limit exceeded
4 Halted 0 ms 0 KB -