Submission #417087

#	Time	Username	Problem	Language	Result	Execution time	Memory
417087		keko37	A Difficult(y) Choice (BOI21_books)	C++14	100 / 100	2 ms	328 KiB

books

#include <bits/stdc++.h>
#include "books.h"

using namespace std;
//
// --- Sample implementation for the task books ---
//
// To compile this program with the sample grader, place:
//     books.h books_sample.cpp sample_grader.cpp
// in a single folder and run:
//     g++ books_sample.cpp sample_grader.cpp
// in this folder.
//

typedef long long llint;

const int MAXN = 100005;
int n;
llint val[MAXN], bio[MAXN];

vector <int> get_bio () {
	vector <int> res;
	for (int i = 1; i <= n; i++) {
		if (bio[i]) res.push_back(i);
	}
	return res;
}

void solve (int N, int k, llint a, int s) {
	n = N;
	llint sum = 0;
	for (int i = 1; i <= k - 1; i++) {
		val[i] = skim(i);
		sum += val[i];
	}
	
	if (sum >= a) {
		sum += skim(k);
		if (a <= sum && sum <= 2 * a) {
			vector <int> tmp;
			for (int i = 1; i <= k; i++) {
				tmp.push_back(i);
			}
			answer(tmp);
		} else {
			impossible();
		}
		return;
	}
	
	int lo = k, hi = n + 1;
	while (lo < hi) {
		int mid = (lo + hi) / 2;
		val[mid] = skim(mid);
		if (val[mid] > a) {
			hi = mid;
		} else {
			lo = mid + 1;
		}
	}
	
	if (lo != n + 1 && sum + val[lo] <= 2 * a) {
		vector <int> tmp;
		for (int i = 1; i <= k - 1; i++) tmp.push_back(i);
		tmp.push_back(lo);
		answer(tmp);
		return;
	}
	if (lo == k) return;
	
	val[lo - 1] = skim(lo - 1);
	sum += val[lo - 1];
	for (int i = 1; i <= k - 1; i++) bio[i] = 1;
	bio[lo - 1] = 1;
	if (a <= sum && sum <= 2 * a) {
		answer(get_bio());
		return;
	}
	for (int i = 1; i <= k - 1; i++) {
		sum -= val[k - i];
		bio[k - i] = 0;
		val[lo - 1 - i] = skim(lo - 1 - i);
		sum += val[lo - 1 - i];
		bio[lo - 1 - i] = 1;
		if (a <= sum && sum <= 2 * a) {
			answer(get_bio());
			return;
		}
	}
	impossible();
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 10 / 10
• Subtask 4: 15 / 15
• Subtask 5: 15 / 15
• Subtask 6: 20 / 20
• Subtask 7: 20 / 20