oj.uz

Submission #1106466

# Submission time Handle Problem Language Result Execution time Memory
1106466 2024-10-30T12:03:35 Z xnqs Watching (JOI13_watching) C++17
0 / 100
 1000 ms 31824 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[2001][2001];

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) {
	if (double(p+q)/x >= 0.95 && cap >= 15) {
		return 1;
	}

	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;
		}
	}

	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);
	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
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 160 ms 31568 KB Output is correct
2 Correct 28 ms 31568 KB Output is correct
3 Correct 222 ms 31568 KB Output is correct
4 Correct 47 ms 31568 KB Output is correct
5 Correct 28 ms 31568 KB Output is correct
6 Correct 44 ms 31568 KB Output is correct
7 Correct 194 ms 31568 KB Output is correct
8 Correct 216 ms 31568 KB Output is correct
9 Correct 243 ms 31568 KB Output is correct
10 Correct 180 ms 31568 KB Output is correct
11 Correct 221 ms 31568 KB Output is correct
12 Incorrect 11 ms 31736 KB Output isn't correct
13 Halted 0 ms 0 KB -

Subtask #2
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 201 ms 31824 KB Output is correct
2 Correct 28 ms 31568 KB Output is correct
3 Correct 494 ms 31824 KB Output is correct
4 Execution timed out 1062 ms 31824 KB Time limit exceeded
5 Halted 0 ms 0 KB -