제출 #850708

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
850708		d4xn	A Difficult(y) Choice (BOI21_books)	C++17	5 / 100	63 ms	1364 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.
//

#define ll long long

const ll N = 1e5+5;

ll dp[N];

/*
ll pw(ll x, ll y) {
  int sum = 0;
  for (int i = 0; i < y; i++) {
    sum += x+i;
  }
  return sum;
}

ll pw2(ll x, ll y) {
  int sum = 0;
  for (int i = 0; i < y; i++) {
    sum += x-i;
  }
  return sum;
}*/

int sum(int x, int y) {
  int cnt = 0;
  for (int i = 0; i < y; i++) {
    if (dp[x+i] == -1) dp[x+i] = skim(x+i);
    cnt += dp[x+i];
  }
  return cnt;
}

int n, k, s;
ll a;
vector<ll> v, pre;
vector<int> ans;
bool ended;

void generate(int idx, int prev, ll sum) {
    if (ended) return;
 
    if (sum > a*2) return;
 
    if (n-prev < k-idx) return;
 
    if (sum + pre[n] - pre[n-(k-idx)] < a) return;
 
    if (idx == k) {
        if (a <= sum && sum <= a*2) {
            ended = 1;
            return;
        }
        return;
    }
 
    for (int i = prev+1; i <= n; i++) {
        ans[idx] = i;
        generate(idx+1, i, sum + v[i]);
        if (ended) return;
    }
}

void solve(int N, int K, long long A, int S) {
    // TODO implement this function
    /*
    if (skim(2) == 42) {
        impossible();
    } else {
        answer({1, 3});
    }
    */

    memset(dp, -1, sizeof(dp));
    
    if (S == N && N <= 1000 && K == 3) {
      n = N;
    k = K;
    a = A;
    s = S;
 
    v.resize(n+1);
    pre.resize(n+1, 0);
    for (int i = 1; i <= n; i++) {
        v[i] = skim(i);
        pre[i] = pre[i-1] + v[i];
    }
 
    ended = 0;
    ans.resize(k);
    generate(0, 0, 0ll);
    if (!ended) impossible();
    answer(ans);
    }

    ll l = 1;
    ll r = N-K;
    while (l < r) {
      ll mid = (l+r)>>1;
      int x = sum(mid, K);
      if (x < A) l = mid+1;
      else if (x > A*2) r = mid-1;
      else {
        l = r = mid;
        break;
      }
    }

    int x = sum(l, K);
    if (x < A || A*2 < x) impossible();

    vector<int> ans(K);
    for (int i = 0; i < K; i++) {
      ans[i] = l+i;
    }
    answer(ans);

/*
    l = L;
    r = N;
    while (l < r) {
      ll mid = (l+r+1)>>1;
      dp[mid] = skim(mid);
      if (pw2(dp[mid], K) > A*2) r = mid-1;
      else l = mid;
      //cerr << mid << " " << dp[mid] << " " << K << " " << A << " " << l << " " << r << endl;
    }
    ll R = l;

    if (R-L+1 >= K) {
      vector<int> ans;
      int cnt = 0;
      for (int i = L; i <= R; i++) {
        ans.push_back(i);
        cnt++;
        if (cnt == K) break;
      }
      answer(ans);
    }
    else impossible();
*/

/*
    ll x = l;
    for (ll i = 1; i < K; i++) {
      if (x+i <= N) dp[x+i] = skim(x+i);
      if (x-i > 0) dp[x-i] = skim(x-i);
    }

    vector<ll> v;
    for (int i = x-K+1; i <= x+K-1; i++) {
      if (0 < i && i <= N) v.push_back(i);
    }
    ll sz = v.size();

    for (ll mask = 0; mask < (1ll << sz); mask++) {
      if (__builtin_popcount(mask) != K) continue;
      vector<int> ans;
      ll sum = 0;
      for (int i = 0; i < sz; i++) {
        if ((mask >> i) & 1ll) {
          ans.push_back(v[i]);
          sum += dp[v[i]];
        }
      }
      if (A <= sum && sum <= A*2) {
        answer(ans);
        return;
      }
    }
    impossible();
    */
}

/*
#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.
//
 
#define ll long long
 
int n, k, s;
ll a;
vector<ll> v, pre;
vector<int> ans;
bool ended;
 
void generate(int idx, int prev, ll sum) {
    if (ended) return;
 
    if (sum > a*2) return;
 
    if (n-prev < k-idx) return;
 
    if (sum + pre[n] - pre[n-(k-idx)] < a) return;
 
    if (idx == k) {
        if (a <= sum && sum <= a*2) {
            ended = 1;
            return;
        }
        return;
    }
 
    for (int i = prev+1; i <= n; i++) {
        ans[idx] = i;
        generate(idx+1, i, sum + v[i]);
        if (ended) return;
    }
}
 
void solve(int N, int K, long long A, int S) {
    // TODO implement this function
    // impossible()
    // answer()
    // puedo hacer S preguntas
    // hay N libros
    // ordenados de mayor a menor por precio
    // tengo que comprar K
    // y la suma tiene que ser >= A y <= A*2
 
    n = N;
    k = K;
    a = A;
    s = S;
 
    v.resize(n+1);
    pre.resize(n+1, 0);
    for (int i = 1; i <= n; i++) {
        v[i] = skim(i);
        pre[i] = pre[i-1] + v[i];
    }
 
    ended = 0;
    ans.resize(k);
    generate(0, 0, 0ll);
    if (!ended) impossible();
    answer(ans);
}
*/

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