Submission #399543

#	Time	Username	Problem	Language	Result	Execution time	Memory
399543		Temmie	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	3 ms	1152 KiB

books

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

typedef long long ll;

void solve(int n, int k, ll a, int s) {
	
	std::vector <ll> vals(n + 1, -1), use;
	vals[n] = skim(n);
	if (vals[n] * ll(k) < a) {
		impossible();
		return;
	}
	int l = k, r = n;
	while (l < r) {
		int mid = (l + r) >> 1;
		if (vals[mid] == -1LL) vals[mid] = skim(mid);
		if (ll(k) * vals[mid] >= a) r = mid;
		else l = mid + 1;
	}
	std::vector <int> res;
	ll sum = 0;
	for (int i = 1 + l - k; i < l + 1; i++) {
		if (vals[i] == -1LL) vals[i] = skim(i);
		res.push_back(i);
		use.push_back(vals[i]);
	}
	for (ll x : use) sum += x;
	if (a <= sum) {
		if (sum <= a + a) answer(res);
		else impossible();
		return;
	}
	for (int i = l + 1; i < 1 + l + k; i++) {
		if (vals[i] == -1LL) vals[i] = skim(i);
		sum += vals[i];
		sum -= use[i - l - 1];
		res.push_back(i);
		if (a <= sum && sum <= a + a) {
			std::vector <int> ans;
			for (int j = i - l; j < (int)res.size(); j++) {
				ans.push_back(res[j]);
			}
			answer(ans);
			return;
		} else if (sum > a + a) {
			ll newsum = vals[i];
			std::vector <int> ans = { i };
			for (int j = 1; j < k; j++) {
				ans.push_back(j);
				if (vals[j] == -1LL) vals[j] = skim(j);
				newsum += vals[j];
			}
			if (newsum >= a && newsum <= a + a) {
				std::sort(ans.begin(), ans.end()); // ???
				answer(ans);
				return;
			}
			impossible();
			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