Submission #721156

#	Time	Username	Problem	Language	Result	Execution time	Memory
721156		FatihSolak	A Difficult(y) Choice (BOI21_books)	C++17	30 / 100	1 ms	208 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.
//

void solve(int n, int k, long long a, int s){
    int l = 1,r = n+1;
    while(l < r){
        int m = (l+r)/2;
        if(skim(m) <= a){
            l = m + 1;
        }
        else r = m;
    }
    vector<pair<int,long long>> x;
    vector<pair<int,long long>> y;
    for(int i = 1;i<=k;i++){
        x.push_back({i,skim(i)});
    }
    if(l < k){
        impossible();
        return;
    }
    if(l != n+1){
        long long sum = skim(l);
        for(int i = 0;i<k-1;i++){
            sum += x[i].second;
        }
        if(a <= sum && sum <= 2*a){
            vector<int> ret;
            for(int i = 1;i<=k-1;i++){
                ret.push_back(i);
            }
            ret.push_back(l);
            answer(ret);
            return;
        }
    }
    if(l == k){
        impossible();
        return;
    }
    for(int i = k;i>=1;i--){
        y.push_back({l-i,skim(l-i)});
    }
    long long sum = 0;
    for(auto u:x){
        sum += u.second;
    }
    if(a <= sum && sum <= 2*a){
        vector<int> ret;
        for(int i = 1;i<=k;i++){
            ret.push_back(i);
        }
        answer(ret);
        return;
    }
    if(sum > 2*a){
        impossible();
        return;
    }
    for(int i = 1;i<=k;i++){
        sum -= x[k-i].second;
        sum += y[k-i].second;
        if(a <= sum && sum <= 2*a){
            vector<int> ret;
            for(int j = 1;j<=k-i;j++){
                ret.push_back(i);
            }
            for(int j = k-1;j>=k-i;j--){
                ret.push_back(y[j].first);
            }
            answer(ret);
            sort(ret.begin(),ret.end());
            return;
        }
        assert(sum < a);
    }
    impossible();
}

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