Submission #850686

#	Time	Username	Problem	Language	Result	Execution time	Memory
850686		vjudge1	A Difficult(y) Choice (BOI21_books)	C++17	0 / 100	2 ms	1236 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.
//

void solve(int N, int K, long long A, int S) {
    // TODO implement this function
  vector<long long> x(N+1);
  for(long long i = 1; i<= N; i++) x[i] = skim(i);
  vector<pair<long long,long long>> ans;
  vector<long long> in;
  map<long long,long long> idx;
  x[0] = x[1];  
  for(long long i = 0; i<=N; i++) idx[x[i]] = i;
  vector<long long> used(N+1);
  for(long long i = 1; i<=N; i++){
    long long s = 2*A; s-=x[i];
    long long a = *lower_bound(x.begin(),x.end(),s);
    if(x[i] + a <= 4*A && !used[i] && !used[idx[a]]) ans.push_back({min(idx[a],i),max(i,idx[a])}), used[i] = 1, used[idx[a]] =1;
    if(A <= x[i] && x[i] <= 2*A) in.push_back(i);
  }
  if(2*ans.size() < K - 1){
    impossible();
    return;
  }
  vector<long long> used1(N+1);
  vector<int> ans1;
  for(long long i = 0; i<K/2; i++){
    used1[ans[i].first] = used1[ans[i].second] = 1;
    ans1.push_back(ans[i].first); ans1.push_back(ans[i].second);
  }
  if(K%2 == 1){
    for(long long i : in){
      if(!used1[i]){
        ans1.push_back(i); break;
      }
    }
  }
  if(ans1.size() != K) impossible();
  else answer(ans1);
  
}

Compilation message (stderr)

books.cpp: In function 'void solve(int, int, long long int, int)':
books.cpp:32:19: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   32 |   if(2*ans.size() < K - 1){
      |      ~~~~~~~~~~~~~^~~~~~~
books.cpp:49:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   49 |   if(ans1.size() != K) impossible();
      |      ~~~~~~~~~~~~^~~~

• Subtask 1: 0 / 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