Submission #1106455

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
1106455	2024-10-30T11:17:50 Z	xnqs	Watching (JOI13_watching)	C++17	50 / 100	390 ms	262144 KB

watching

// dp solution just so i can see if its correct
 
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <cstring>
 
int x, p, q;
std::vector<int> arr;
std::vector<std::vector<std::vector<char>>> dp;
 
char sol(int pos, int a, int b, int cap) {
	if (a>p||b>q) {
		return 0;
	}
	if (pos==x) {
		return 1;
	}
	if (dp[pos][a][b]!=-1) {
		return dp[pos][a][b];
	}
 
	char ret = 0;
	for (int i = pos; i < x; i++) {
		if (arr[i]-arr[pos]+1 <= cap) {
			ret |= sol(i+1,a+1,b,cap);
		}
		if (arr[i]-arr[pos]+1 <= 2*cap) {
			ret |= sol(i+1,a,b+1,cap);
		}
	}
	return dp[pos][a][b] = ret;
}
 
bool can_solve(int cap, bool debug = 0) {
	dp.assign(x,std::vector<std::vector<char>>(p+1,std::vector<char>(q+1,-1)));
	return sol(0,0,0,cap);
}
 
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	3 ms	336 KB	Output is correct
2	Correct	1 ms	336 KB	Output is correct
3	Correct	1 ms	336 KB	Output is correct
4	Correct	58 ms	848 KB	Output is correct
5	Correct	5 ms	336 KB	Output is correct
6	Correct	5 ms	336 KB	Output is correct
7	Correct	5 ms	336 KB	Output is correct
8	Correct	14 ms	336 KB	Output is correct
9	Correct	16 ms	336 KB	Output is correct
10	Correct	76 ms	616 KB	Output is correct
11	Correct	90 ms	592 KB	Output is correct
12	Correct	178 ms	848 KB	Output is correct
13	Correct	22 ms	336 KB	Output is correct
14	Correct	19 ms	512 KB	Output is correct
15	Correct	20 ms	504 KB	Output is correct

Subtask #2

0 / 50.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	390 ms	760 KB	Output is correct
2	Correct	1 ms	336 KB	Output is correct
3	Runtime error	170 ms	262144 KB	Execution killed with signal 9
4	Halted	0 ms	0 KB	-