Submission #530454

#	Time	Username	Problem	Language	Result	Execution time	Memory
530454		chaoyue	A Difficult(y) Choice (BOI21_books)	C++14	100 / 100	2 ms	1096 KiB

books

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

#define ll long long

void solve(int n, int k, ll A, int S) {
    vector<ll> v(n+1, 0);
    vector<int> ans;
    int l=0, r=n, m;
    ll pre=0, sum=0;
    for(int i=1; i<k; i++){
    	v[i] = skim(i);
    	pre += v[i];
    	if(pre > A * 2ll){
    		impossible();
    		return;
		}
	}
	//lower bound binary search
	
	while(r-l > 1){
		m = (l+r)/2;
		if(!v[m]) v[m] = skim(m);
		if(v[m] * (ll)k < A){
			l = m;
		}
		else{
			r = m;
		}
	}
	if(!v[r]) v[r] = skim(r);
	l = r;
	for(int i=l-1; i>= max(1, l-k+1); i--){
		if(!v[i]) v[i] = skim(i);
	}
	for(int i=l+1; i<=min(n, l+k-1); i++){
		if(!v[i]) v[i] = skim(i);
	}
	for(int i=max(0, l-k); i<max(l, k); i++){
		sum += v[i];
		if(sum > A * 2ll) break;
	}
	for(int i=max(1, l-k+1); i<=min(l, n-k+1); i++){
		sum += v[i+k-1]-v[i-1];
		if(sum > A * 2ll) break;
		if(sum >= A){
			for(int j=i; j<i+k; j++){
				ans.push_back(j);
			}
			answer(ans);
			return;
		}
	}
	for(int i=max(k, l-k+1); i<=min(n, l+k-1); i++){
		if(v[i] + pre > A * 2ll) break;
		if(v[i] + pre >= A){
			for(int j=1; j<k; j++){
				ans.push_back(j);
			}
			ans.push_back(i);
			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