Submission #725504

#	Time	Username	Problem	Language	Result	Execution time	Memory
725504		josanneo22	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	1 ms	336 KiB

books

#include "books.h"
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
 
int n, k;
ll arr[100002];
ll arr2[100002];
int s, lim;
 
void solve(int N, int K, ll A, int S){
    n = N, k = K, s = S, lim = A;
 
    for(int i=1; i<=k; i++) arr[i] = skim(i);
    int MIN = 1, MAX = n, LOC = n+1;
    ll VAL = 1e18;
    while(MIN <= MAX){
        int MID = (MIN + MAX) / 2;
        ll tmp = skim(MID);
        if(tmp >= A){
            VAL = tmp;
            LOC = MID;
            MAX = MID-1;
        }
        else MIN = MID+1;
    }
 
    if(LOC != n+1){
        ll sum = 0;
        for(int i=1; i<k; i++) sum += arr[i];
        sum += VAL;
        if(A <= sum && sum <= A+A){
            vector<int> v;
            for(int i=1; i<k; i++) v.push_back(i);
            v.push_back(LOC);
            answer(v);
            return;
        }
    }
 
    LOC--;
    if(LOC < k) impossible();
 
    for(int i=1; i<=k; i++){
        arr2[i] = skim(LOC+1-i);
    }
 
    for(int i=0; i<=k; i++){
        ll sum = 0;
        for(int j=1; j<=i; j++) sum += arr[j];
        for(int j=1; j<=k-i; j++) sum += arr2[j];
        if(A <= sum && sum <= A+A){
            vector<int> v;
            for(int j=1; j<=i; j++) v.push_back(j);
            for(int j=1; j<=k-i; j++) v.push_back(LOC+1-j);
            answer(v);
            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