Submission #660786

#	Time	Username	Problem	Language	Result	Execution time	Memory
660786		600Mihnea	medians (balkan11_medians)	C++17	100 / 100	84 ms	12748 KiB

medians

bool home = 0;

#include <bits/stdc++.h>

using namespace std;

const int N = 200000 + 7;
int n;
int b[N];
int a[N];
set<int> s;

int nxt_up(int i)
{
  auto it = s.lower_bound(i);
  assert(it != s.end());
  int sol = *it;
  s.erase(it);
  return sol;
}

int nxt_down(int i)
{
  auto it = s.lower_bound(i + 1);
  assert(it != s.begin());
  it--;
  int sol = *it;
  s.erase(it);
  return sol;
}

int main()
{
  if (home == 0)
  {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  }
  else
  {
    freopen ("input.txt", "r", stdin);
  }

  cin >> n;
  for (int i = 1; i <= 2 * n - 1; i++)
  {
    s.insert(i);
  }
  for (int i = 1; i <= n; i++)
  {
    cin >> b[i];
  }
  a[1] = nxt_up(b[1]);
  for (int i = 2; i <= n; i++)
  {
    if (b[i] == b[i - 1])
    {
      a[2 * i - 2] = nxt_up(1);
      a[2 * i - 1] = nxt_down(2 * n - 1);
      continue;
    }
    if (b[i] < b[i - 1])
    {
      if (s.count(b[i]))
      {
        a[2 * i - 2] = nxt_up(b[i]);
        a[2 * i - 1] = nxt_up(1);
      }
      else
      {
        a[2 * i - 2] = nxt_up(1);
        a[2 * i - 1] = nxt_up(1);
      }
      continue;
    }
    if (b[i] > b[i - 1])
    {
      if (s.count(b[i]))
      {
        a[2 * i - 2] = nxt_down(b[i]);
        a[2 * i - 1] = nxt_down(2 * n - 1);
      }
      else
      {
        a[2 * i - 2] = nxt_down(2 * n - 1);
        a[2 * i - 1] = nxt_down(2 * n - 1);
      }
      continue;
    }
    assert(0);
  }
  for (int i = 1; i <= 2 * n - 1; i++)
  {
    cout << a[i] << " ";
  }
  cout << "\n";
  return 0;
}

Compilation message (stderr)

medians.cpp: In function 'int main()':
medians.cpp:40:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |     freopen ("input.txt", "r", stdin);
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 65 / 65
• Subtask 2: 35 / 35