Submission #958950

#	Time	Username	Problem	Language	Result	Execution time	Memory
958950		phoenix0423	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	3 ms	608 KiB

books

#include<bits/stdc++.h>
#include "books.h"
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
#define eb emplace_back
#define f first
#define s second

// int skim(int x){
//     cout<<"skim : "<<x<<"\n";
//     cin>>x;
//     return x;
// }
// void impossible(){
//     cout<<"IMPOSSIBLE\n";
// }
// void answer(vector<int> v){
//     cout<<"answer : ";
//     for(auto x : v) cout<<x<<" ";
//     cout<<"\n";
// }
void solve(int n, int k, ll a, int s){
    map<int, ll> mp;
    auto get = [&](int x) -> ll {
        if(mp[x]) return mp[x];
        return mp[x] = skim(x);
    };
    // find first > A
    int l = 1, r = n + 1;
    while(l + 1 < r){
        int m = (l + r) / 2;
        ll x = get(m);
        if(x > a) r = m;
        else l = m;
    }
    if(r < k){
        impossible();
    }
    ll ttl = 0;
    for(int i = 1; i <= k; i++) ttl += get(i);
    if(ttl > 2 * a){
        impossible();
    }
    if(ttl >= a){
        vector<int> ans(k);
        iota(ans.begin(), ans.end(), 1);
        answer(ans);
    }
    if(r <= n){
        if(ttl - get(k) + get(r) <= 2 * a){
            vector<int> ans(k - 1);
            iota(ans.begin(), ans.end(), 1);
            ans.pb(r);
            answer(ans);
        }
    }
    if(r <= 2 * k){
        for(int i = k + 1; i < r; i++){
            ttl += get(i);
            ttl -= get(i - k);
            if(ttl >= a){
                vector<int> ans(k);
                iota(ans.begin(), ans.end(), i - k + 1);
                answer(ans);
            }
        }
        impossible();
    }
    for(int i = r - k; i < r; i++){
        ttl += get(i);
        ttl -= get(i - (r - k) + 1);
        if(ttl >= a){
            vector<int> ans;
            for(int j = i - (r - k) + 2; j <= k; j++) ans.pb(j);
            for(int j = r - k; j <= i; j++) ans.pb(j);
            answer(ans);
        }
    }
    impossible();
}

// signed main(void){
//     int n, k, a, s;
//     cin>>n>>k>>a>>s;
//     solve(n, k, a, s);
// }

• 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