Submission #528897

#	Time	Username	Problem	Language	Result	Execution time	Memory
528897		OttoTheDino	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	3 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.
//

#define rep(i,s,e)          for (ll i = s; i <= e; ++i)
#define all(a)              a.begin(), a.end()
typedef long long ll;

const ll mx = 2e5;
ll x[mx];

ll get (int i) {
    if (!x[i]) x[i] = skim(i);
    return x[i];
}

void solve(int n, int k, long long a, int S) {
    vector<int> ans(k);
    iota(all(ans),1);

    ll s = 0;
    rep (i,1,k) {
        x[i] = get(i);
        s += x[i];
    }

    if (s>2*a) impossible();

    else if (s>=a) {
        answer(ans);
        return;
    }

    else {
        ll lo = k+1, hi = n+1;
        while (lo<hi) {
            ll mid  = (lo+hi)/2;
            x[mid] = get(mid);
            if (x[mid]>=a) hi = mid;
            else lo = mid+1;
        }
        if (lo!=n+1) {
            if (s+x[lo]-x[k]<=2*a) {
                ans[k-1] = lo;
                answer(ans);
                return;
            }
        }
        n = --lo;
        rep (i,1,k) {
            x[n-i+1] = get(n-i+1);
            s += x[n-i+1] - x[k-i+1];
            ans[k-i] = n-i+1;
            if (s>=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