oj.uz

Submission #1106566

# Submission time Handle Problem Language Result Execution time Memory
1106566 2024-10-30T16:38:56 Z xnqs Watching (JOI13_watching) C++17
50 / 100
 1000 ms 11888 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][727];

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 = 1000;
		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 60 ms 11600 KB Output is correct
2 Correct 61 ms 11600 KB Output is correct
3 Correct 61 ms 11600 KB Output is correct
4 Correct 50 ms 11600 KB Output is correct
5 Correct 61 ms 11600 KB Output is correct
6 Correct 49 ms 11768 KB Output is correct
7 Correct 47 ms 11824 KB Output is correct
8 Correct 59 ms 11600 KB Output is correct
9 Correct 63 ms 11600 KB Output is correct
10 Correct 62 ms 11600 KB Output is correct
11 Correct 61 ms 11832 KB Output is correct
12 Correct 70 ms 11600 KB Output is correct
13 Correct 62 ms 11600 KB Output is correct
14 Correct 60 ms 11600 KB Output is correct
15 Correct 47 ms 11600 KB Output is correct

Subtask #2
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 60 ms 11856 KB Output is correct
2 Correct 64 ms 11600 KB Output is correct
3 Execution timed out 1046 ms 11888 KB Time limit exceeded
4 Halted 0 ms 0 KB -