제출 #1251363

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1251363		ogkostya	3개의 봉우리 (IOI25_triples)	C++20	79.25 / 100	193 ms	37148 KiB

triples

#include "triples.h"
#include <set>

long long count_triples(std::vector<int> H)
{

  int n = H.size();
  // if (n < 1000000)
  //   return 0;
  std::vector<std::set<std::pair<int, int>>> s(n, std::set<std::pair<int, int>>());

  for (int j = 1; j < n - 1; j++)
  {
    int i, k;
    i = j - H[j];
    if (i >= 0)
    {
      k = j + H[i];
      if (k < n && k - i == H[k])
        s[i].insert(std::pair<int, int>(j, k));

      k = i + H[i];
      if (k < n && k > j && H[k] == k - j)
        s[i].insert(std::pair<int, int>(j, k));
    }

    k = j + H[j];
    if (k < n)
    {
      i = j - H[k];
      if (i >= 0 && k - i == H[i])
        s[i].insert(std::pair<int, int>(j, k));
      i = k - H[k];
      if (i >= 0 && i < j && j - i == H[i])
        s[i].insert(std::pair<int, int>(j, k));
    }
  }

  long long ans = 0;
  for (int i = 0; i < s.size(); i++)
  {
    ans += s[i].size();
  }

  std::vector<std::vector<int>> l(n, std::vector<int>());
  std::vector<std::vector<int>> r(n, std::vector<int>());
  for (int i = 0; i < n; i++)
  {
    int j = i + H[i];
    if (j < n)
    {
      int k = i + H[j];
      if (k < n && k > j && k - H[k] == j)
        ans++;

      l[j].push_back(i);
    }
    {
      int k = i - H[i];
      if (k >= 0)
        r[k].push_back(i);
    }
  }

  for (int jj = 0; jj < n; jj++)
  {
    if (l[jj].size() == 0 || r[jj].size() == 0)
      continue;
    if (1LL * l[jj].size() * r[jj].size() <= n)
    {
      for (const int &i : l[jj])
      {
        for (const int &k : r[jj])
        {
          if (H[i] == H[k])
            continue;
          int j = i + H[k];
          if (H[j] == k - i)
            ans++;
        }
      }
    }
    else
    {
      for (int j = jj - 1; j >= 0; j--)
      {
        int d = jj - j;
        if (d < H[j])
          continue;
        d += H[j];
        if ((d & 1) == 1)
          continue;
        d >>= 1;
        int x = H[j] - d;
        if (x == d)
          continue;
        int i = jj - d;
        int k = jj + x;
        if (k - H[k] == jj && i + H[i] == jj)
          ans++;
      }

      for (int j = jj + 1; j < n; j++)
      {
        int d = j - jj;
        if (d < H[j])
          continue;
        d += H[j];
        if ((d & 1) == 1)
          continue;
        d >>= 1;
        int x = H[j] - d;
        if (x == d)
          continue;
        int i = jj - x;
        int k = jj + d;
        if (k - H[k] == jj && i + H[i] == jj)
          ans++;
      }
    }
  }

  return ans;
}

int array[] = {3, 1, 2, 1, 4, 3, 2, 7, 6, 5, 6, 3, 4, 5};

std::vector<int> construct_range(int M, int K)
{
  std::vector<int> ans(M, 1);
  for (int i = 0; i < M; i++)
  {
    ans[i] = array[i % 14];
  }
  return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 6 / 6
• Subtask 3: 10 / 10
• Subtask 4: 11 / 11
• Subtask 5: 16 / 16
• Subtask 6: 19 / 19
• Subtask 7: 5 / 5
• Subtask 8: 2.3075 / 5
• Subtask 9: 0.9278 / 5
• Subtask 10: 0.3979 / 5
• Subtask 11: 0.4643 / 5
• Subtask 12: 0.1548 / 5