oj.uz

답안 #1106571

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1106571 2024-10-30T16:40:57 Z xnqs 구경하기 (JOI13_watching) C++17
50 / 100
 490 ms 8440 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][500];

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

# 결과 실행 시간 메모리 Grader output
1 Correct 48 ms 8272 KB Output is correct
2 Correct 48 ms 8272 KB Output is correct
3 Correct 48 ms 8272 KB Output is correct
4 Correct 42 ms 8272 KB Output is correct
5 Correct 49 ms 8272 KB Output is correct
6 Correct 48 ms 8284 KB Output is correct
7 Correct 39 ms 8272 KB Output is correct
8 Correct 49 ms 8272 KB Output is correct
9 Correct 40 ms 8272 KB Output is correct
10 Correct 41 ms 8272 KB Output is correct
11 Correct 44 ms 8272 KB Output is correct
12 Correct 48 ms 8272 KB Output is correct
13 Correct 42 ms 8272 KB Output is correct
14 Correct 46 ms 8272 KB Output is correct
15 Correct 52 ms 8440 KB Output is correct

Subtask #2
0 / 50.0

# 결과 실행 시간 메모리 Grader output
1 Correct 39 ms 8272 KB Output is correct
2 Correct 40 ms 8272 KB Output is correct
3 Incorrect 490 ms 8272 KB Output isn't correct
4 Halted 0 ms 0 KB -