Submission #1286625

#	Time	Username	Problem	Language	Result	Execution time	Memory
1286625		SmuggingSpun	A Difficult(y) Choice (BOI21_books)	C++20	100 / 100	64 ms	1168 KiB

books

#include <bits/stdc++.h>
#include "books.h"
using namespace std;
typedef long long ll;
const int lim = 1e5 + 5;
ll cost[lim];
ll get(int i){
	if(cost[i] != -1){
		return cost[i];
	}
	return cost[i] = skim(i);
}
void solve(int n, int k, ll A, int S){
	memset(cost, -1, sizeof(cost));
	if(S == n){
		for(int i = 1; i <= n; i++){
			get(i);
		}
		ll pref = accumulate(cost + 1, cost + k + 1, 0LL);
		if(pref > (A << 1LL)){
			impossible();
			return;
		}
		vector<int>ans;
		if(pref >= A){
			for(int i = 1; i <= k; i++){
				ans.push_back(i);
			}
			answer(ans);
			return;
		}
		ll sum = pref;
		for(int i = n, j = k; i > j && j > 0; i--){
			ll alt = sum - cost[j] + cost[i];
			if(alt <= (A << 1LL)){
				if(alt >= A){
					for(int t = j - 1; t > 0; t--){
						ans.push_back(t);
					}
					ans.push_back(i);
					answer(ans);
					return;
				}
				pref -= cost[j--];
				sum = alt;
				ans.push_back(i);
			}
		}
		impossible();
		return;
	}
	if(S >= 170){
		ll pref = 0;
		for(int i = 1; i <= k; i++){
			pref += get(i);
		}
		if(pref > (A << 1LL)){
			impossible();
			return;
		}
		vector<int>ans;
		if(pref >= A){
			for(int i = 1; i <= k; i++){
				ans.push_back(i);
			}
			answer(ans);
			return;
		}
		ll sum = pref;
		for(int j = k, pre = n + 1; j > 0; j--){
			int low = j + 1, high = pre - 1, i = -1;
			while(low <= high){
				int mid = (low + high) >> 1;
				if(sum - get(j) + get(mid) <= (A << 1LL)){
					low = (i = mid) + 1;
				}
				else{
					high = mid - 1;
				}
			}
			if(i == -1){
				impossible();
				return;
			}
			ll alt = sum - get(j) + get(i);
			if(alt >= A){
				for(int t = j - 1; t > 0; t--){
					ans.push_back(t);
				}
				ans.push_back(i);
				answer(ans);
				return;
			}
			pref -= get(j);
			sum = alt;
			ans.push_back(pre = i);
		}
		impossible();
		return;
	}
	ll pref = 0;
	vector<int>ans(k);
	for(int i = 1; i <= k; i++){
		pref += get(ans[i - 1] = i);
	}
	if(pref > (A << 1LL)){
		impossible();
		return;
	}
	if(pref >= A){
		answer(ans);
		return;
	}
	int low = 1, high = n, last_small = 0;
	while(low <= high){
		int mid = (low + high) >> 1;
		if(get(mid) < A){
			low = (last_small = mid) + 1;
		}
		else{
			high = mid - 1;
		}
	}
	if(last_small < n){
		if(pref - get(k) + get(last_small + 1) <= (A << 1LL)){
			ans[k - 1] = last_small + 1;
			answer(ans);
			return;
		}
	}
	if(last_small < k){
		impossible();
		return;
	}
	for(int i = k, j = k; i > 0; i--){
		ll alt = pref + get(last_small - i + 1) - get(j);
		if(alt <= (A << 1LL)){
			ans[--j] = last_small - i + 1;
			if((pref = alt) >= A){
				answer(ans);
				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