Submission #1106449

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
1106449	2024-10-30T10:56:57 Z	xnqs	Watching (JOI13_watching)	C++17	50 / 100	167 ms	2640 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;
char dp[101][101][101];

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) {
	memset(dp,-1,sizeof(dp));
	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	4 ms	1360 KB	Output is correct
2	Correct	2 ms	1360 KB	Output is correct
3	Correct	2 ms	1360 KB	Output is correct
4	Correct	53 ms	1360 KB	Output is correct
5	Correct	7 ms	1360 KB	Output is correct
6	Correct	7 ms	1360 KB	Output is correct
7	Correct	6 ms	1360 KB	Output is correct
8	Correct	16 ms	1360 KB	Output is correct
9	Correct	18 ms	1360 KB	Output is correct
10	Correct	77 ms	1360 KB	Output is correct
11	Correct	90 ms	1528 KB	Output is correct
12	Correct	167 ms	1360 KB	Output is correct
13	Correct	21 ms	1360 KB	Output is correct
14	Correct	20 ms	1360 KB	Output is correct
15	Correct	20 ms	1360 KB	Output is correct

Subtask #2

0 / 50.0

#	Verdict	Execution time	Memory	Grader output
1	Runtime error	4 ms	2640 KB	Execution killed with signal 11
2	Halted	0 ms	0 KB	-