Submission #532814

#	Time	Username	Problem	Language	Result	Execution time	Memory
532814		safaricola	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	2 ms	1096 KiB

books

#include <bits/stdc++.h>
#include "books.h"
using namespace std;
typedef long long ll;
typedef pair<ll,ll> ii;
//
// --- 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) {
    // TODO implement this function
    int count=0;
    ll b[N+5];
    memset(b,0,sizeof(b));
    int low = 0, high = N + 1;
    while(high - low >= 2)
    {
        int mid = (high + low) / 2;
        count++;
        assert(count<S);
        b[mid]=skim(mid);
        if(b[mid] < A) low = mid;
        else high = mid;
    }
    ll a[K+5];
    memset(a,0,sizeof(a));
    //cout<<low<<endl;
    high=low;
    //if(high<=K-2)impossible();
    for(int i=1; i<=K; i++){
        if(!b[i]){
            count++;
            assert(count<S);
            b[i]=skim(i);
        }
        a[i]=a[i-1]+b[i];
    }
    ll c[K+5];
    memset(c,0, sizeof(c));
    for(int i=high; i>=max(high-K+1,1); i--){
        if(!b[i]){
            count++;
            assert(count<S);
            b[i]=skim(i);
        }
        c[high-i+1]=c[high-i]+b[i];
    }
    //for(int i=1; i<=K; i++)cout<<c[i]<<" ";
    //    cout<<endl;
    if(high<N && !b[high+1]){
            count++;
            assert(count<S);
            b[high+1]=skim(high+1);
    }
    if(high<N && b[high+1]+a[K-1]<=2*A){
        vector<int> v;
        for(int i=1; i<=K-1; i++){
            v.push_back(i);
        }
        v.push_back(high+1);
        answer(v);
    }else{
        for(int i=0; i<=K;i++){
            //printf("i=%d, sum=%lld \n", i,a[i]+c[K-i]);
            if(a[i]+c[K-i]>=A && a[i]+c[K-i]<=2*A){
                vector<int> v;
                for(int j=1; j<=i; j++){
                    v.push_back(j);
                }
                for(int j=0; j<K-i; j++){
                    v.push_back(high-j);
                }
                answer(v);
            }
        }
    }
    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