oj.uz

Submission #1106570

# Submission time Handle Problem Language Result Execution time Memory
1106570 2024-10-30T16:40:35 Z xnqs Watching (JOI13_watching) C++17
50 / 100
 1000 ms 9980 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][600];

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 40 ms 9808 KB Output is correct
2 Correct 41 ms 9808 KB Output is correct
3 Correct 43 ms 9808 KB Output is correct
4 Correct 42 ms 9852 KB Output is correct
5 Correct 44 ms 9808 KB Output is correct
6 Correct 54 ms 9808 KB Output is correct
7 Correct 40 ms 9808 KB Output is correct
8 Correct 40 ms 9808 KB Output is correct
9 Correct 52 ms 9808 KB Output is correct
10 Correct 55 ms 9808 KB Output is correct
11 Correct 57 ms 9852 KB Output is correct
12 Correct 59 ms 9976 KB Output is correct
13 Correct 52 ms 9808 KB Output is correct
14 Correct 51 ms 9808 KB Output is correct
15 Correct 40 ms 9808 KB Output is correct

Subtask #2
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 41 ms 9888 KB Output is correct
2 Correct 43 ms 9980 KB Output is correct
3 Execution timed out 1066 ms 9808 KB Time limit exceeded
4 Halted 0 ms 0 KB -