Submission #1187328

#	Time	Username	Problem	Language	Result	Execution time	Memory
1187328		kl0989e	A Difficult(y) Choice (BOI21_books)	C++20	20 / 100	2 ms	2732 KiB

books

#include "books.h"
#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define fi first
#define se second
#define pb push_back
#define vi vector<int>
#define vl vector<ll>
#define pi pair<int, int>
#define pl pair<ll,ll>
#define all(x) (x).begin(),(x).end()

vl memo(1e5,-1);

ll query(int i) {
	if (memo[i]!=-1) {
		return memo[i];
	}
	return memo[i]=skim(i+1);
}

void solve(int n, int k, ll a, int s) {
	fill(all(memo),-1);
	vl vals(k-1);
	for (int i=0; i<k-1; i++) {
		vals[i]=query(i);
	}
	int l=k-1,r=n-1;
	ll sum=accumulate(all(vals),0ll);
	while (l<=r) {
		int m=l+(r-l)/2;
		ll t=sum+query(m);
		if (t<a) {
			l=m+1;
		}
		else if (t>2*a) {
			r=m-1;
		}
		else {
			vi inds(k);
			iota(all(inds),1);
			inds[k-1]=m+1;
			answer(inds);
		}
	}
	vl mx(n),mn(n);
	for (int i=0; i<n; i++) {
		if (memo[i]!=-1) {
			mn[i]=memo[i];
		}
		else {
			mn[i]=max(mn[i-1],1ll);
		}
	}
	for (int i=n-1; i>=0; i--) {
		if (memo[i]!=-1) {
			mx[i]=memo[i];
		}
		else if (i!=n-1) {
			mx[i]=min((ll)1e17,mx[i+1]-1);
		}
		else {
			mx[i]=1e17;
		}
	}
	l=0,r=n-k;
	while (accumulate(mn.begin()+r,mn.begin()+r+k,0ll)>2*a) {
		r--;
	}
	while (accumulate(mx.begin()+l,mx.begin()+l+k,0ll)<a) {
		l++;
	}
	while (l<=r) {
		int m=l+(r-l)/2;
		ll sum=0;
		for (int i=m; i<m+k; i++) {
			sum+=query(i);
			if (i==m && sum*k+k*(k-1)/2>2*a) {
				sum=2*a+1;
				break;
			}
		}
		if (sum<a) {
			l=m+1;
		}
		else if (sum>2*a) {
			r=m-1;
		}
		else {
			vi inds(k);
			iota(all(inds),m+1);
			answer(inds);
		}
	}
	impossible();
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20