Submission #714912

#	Time	Username	Problem	Language	Result	Execution time	Memory
714912		fadi57	A Difficult(y) Choice (BOI21_books)	C++14	100 / 100	1 ms	324 KiB

books

#include <bits/stdc++.h>
#include "books.h"
//~ #include "grader.cpp"
using namespace std;
#define ll long long
 
map <int, ll> mp;
 
ll ask(int idx){
    if(mp.count(idx)) return mp[idx];
    return mp[idx] = skim(idx);
}
void solve(int N, int K, long long A, int S){
    ll sum = 0;
    set <int> cur;
    for(int i = 1 ; i <= K ; i++){
        sum += ask(i);
        cur.insert(i);
    }
    if(A <= sum && sum <= 2 * A){
        answer(vector <int>(cur.begin(), cur.end()));
        return;
    }
    if(N == K || sum > 2 * A) impossible();
    sum -= ask(K);
    int l = K + 1, r = N;
    while(l <= r){
        int mid = (l + r) / 2;
        if(sum + ask(mid) < A) l = mid + 1;
        else r = mid - 1;
    }
    if(l <= N && A <= sum + ask(l) && sum + ask(l) <= 2 * A){
        cur.erase(K);
        cur.insert(l);
        answer(vector <int>(cur.begin(), cur.end()));
        return;
    }
    sum += ask(K);
    int g = 1, h = l - 1;
    for(int i = 0 ; i < K ; i++){
        cur.erase(g);
        cur.insert(h);
        sum -= ask(g);
        sum += ask(h);
        if(A <= sum && sum <= 2 * A){
            answer(vector <int>(cur.begin(), cur.end()));
            return;
        }
        g++;
        h--;
    }
    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