Submission #1106611

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
1106611	2024-10-30T17:35:53 Z	xnqs	Watching (JOI13_watching)	C++17	50 / 100	164 ms	1532 KB

watching

#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) {
	if (x<=100) {
		memset(dp,-1,sizeof(dp));
		return sol(0,0,0,cap);
	}
	else {
		int a = p, b = q;

		bool mode = 0;
		for (int i = 0; i < x; i++) {
			if (mode==0) {
				--p;
			}
			else {
				--q;
			}

			int j = i;
			while (j+1<x&&arr[j+1]-arr[i]+1<=((mode) ? cap : 2*cap)) {
				++j;
			}
			mode ^= 1;

			if (mode==0) mode ^= !p;
			if (mode==1) mode ^= !q;

			i = j;
		}

		if (p>=0&&q>=0) {
			p = a;
			q = b;
			return 1;
		}
		
		p = a;
		q = b;
		mode = 1;
		for (int i = 0; i < x; i++) {
			if (mode==0) {
				--p;
			}
			else {
				--q;
			}

			int j = i;
			while (j+1<x&&arr[j+1]-arr[i]+1<=((mode) ? cap : 2*cap)) {
				++j;
			}
			mode ^= 1;

			if (mode==0) mode ^= !p;
			if (mode==1) mode ^= !q;

			i = j;
		}

		if (p>=0&&q>=0) {
			p = a;
			q = b;
			return 1;
		}
		
		p = a;
		q = b;
		return 0;
	}
}
 
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	1372 KB	Output is correct
3	Correct	2 ms	1372 KB	Output is correct
4	Correct	52 ms	1360 KB	Output is correct
5	Correct	7 ms	1532 KB	Output is correct
6	Correct	7 ms	1360 KB	Output is correct
7	Correct	6 ms	1368 KB	Output is correct
8	Correct	16 ms	1360 KB	Output is correct
9	Correct	17 ms	1360 KB	Output is correct
10	Correct	100 ms	1360 KB	Output is correct
11	Correct	83 ms	1360 KB	Output is correct
12	Correct	164 ms	1360 KB	Output is correct
13	Correct	22 ms	1360 KB	Output is correct
14	Correct	18 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	Correct	1 ms	336 KB	Output is correct
2	Correct	2 ms	1360 KB	Output is correct
3	Correct	1 ms	336 KB	Output is correct
4	Correct	1 ms	336 KB	Output is correct
5	Correct	1 ms	592 KB	Output is correct
6	Correct	1 ms	480 KB	Output is correct
7	Incorrect	1 ms	336 KB	Output isn't correct
8	Halted	0 ms	0 KB	-