제출 #1059147

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1059147		vjudge1	게임 (IOI14_game)	C++17	0 / 100	0 ms	600 KiB

game

#include "game.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
// #include <iostream>
#include <optional>
#include <unordered_map>
#include <utility>
#include <vector>

using namespace std;

class CityForest {
public:
  explicit CityForest(size_t n) {
    assert(n > 0);
    count = n;

    for (size_t i = 0; i < n; ++i) {
      parents.push_back(i);
    }
    for (size_t i = 0; i < n; ++i) {
      unordered_map<size_t, size_t> i_can_connect_to;
      for (size_t j = 0; j < n; ++j) {
        // cout << "adding " << j << " as a connection of " << i << '\n';
        if (i != j) {
          i_can_connect_to.insert(
              {j, i}); // (component can connect to j from i)
        }
      }
      can_connect_to.push_back(i_can_connect_to);
    }

    sizes = vector<size_t>(n, 1);
  }

  bool are_connected(size_t a, size_t b) {
    return get_representative(a) == get_representative(b);
  }

  void denied_connecting_edge(size_t a, size_t b) {
    // cout << "denied " << a << " and " << b << "\n";
    assert(!are_connected(a, b));

    unordered_map<size_t, size_t> &a_connections =
        can_connect_to.at(get_representative(a));
    unordered_map<size_t, size_t> &b_connections =
        can_connect_to.at(get_representative(b));

    // cout << a << " has " << a_connections.size() << " connections.\n";
    // cout << b << " has " << b_connections.size() << " connections.\n";

    a_connections.erase(b);
    b_connections.erase(a);

    if (a_connections.size() == 1) {
      auto remaining_connection = a_connections.begin();
      size_t from = remaining_connection->second;
      size_t to = remaining_connection->first;
      join(from, to); // mandatory join operation
    }
    if (b_connections.size() == 1) {
      auto remaining_connection = b_connections.begin();
      size_t from = remaining_connection->second;
      size_t to = remaining_connection->first;
      join(from, to); // mandatory join operation
    }
  }

  [[nodiscard]] size_t size_of(size_t k) {
    return sizes.at(get_representative(k));
  }
  [[nodiscard]] size_t size() const { return count; }

private:
  vector<size_t> parents;
  vector<size_t> sizes;
  vector<unordered_map<size_t, size_t>> can_connect_to;
  size_t count = 0;

  void join(size_t absorbed_node, size_t absorbing_node) {
    if (size_of(absorbed_node) > size_of(absorbing_node)) {
      swap(absorbed_node, absorbing_node);
    }
    if (are_connected(absorbed_node, absorbing_node)) {
      return;
    }

    // cout << "joining " << absorbed_node << " & " << absorbing_node << '\n';

    size_t new_size = size_of(absorbed_node) + size_of(absorbing_node);
    size_t remaining_representative = get_representative(absorbing_node);
    size_t absorbed_representative = get_representative(absorbed_node);
    parents.at(absorbed_representative) = remaining_representative;
    sizes.at(remaining_representative) = new_size;

    assert(can_connect_to.at(remaining_representative).size() == 1 ||
           can_connect_to.at(absorbed_representative).size() == 1);
    assert(
        can_connect_to.at(remaining_representative).count(absorbed_node) == 1 &&
        can_connect_to.at(absorbed_representative).count(absorbing_node) == 1);

    if (can_connect_to.at(remaining_representative).size() == 1) {
      can_connect_to.at(remaining_representative) =
          can_connect_to.at(absorbed_representative);
      can_connect_to.at(remaining_representative).erase(absorbing_node);
    } else if (can_connect_to.at(absorbed_representative).size() == 1) {
      can_connect_to.at(remaining_representative).erase(absorbed_node);
    }

    --count;
  }

  [[nodiscard]] size_t get_representative(size_t k) {
    size_t current = k;
    size_t parent = parents.at(k);
    while (current != parent) {
      current = parent;
      parent = parents.at(current);
    }

    size_t representative = current;

    current = k;
    parent = parents.at(k);
    parents.at(k) = representative;
    while (current != parent) {
      current = parent;
      parent = parents.at(current);
      parents.at(current) = representative;
    }

    return representative;
  }
};

optional<CityForest> connected_components; // NOLINT

void initialize(int n) { connected_components = CityForest(n); }

int hasEdge(int u, int v) {
  if (connected_components.value().are_connected(u, v)) {
    // cout << u << " and " << v << " are connected.\n";
    return 1;
  }
  connected_components.value().denied_connecting_edge(u, v);
  return 0;
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 27
• Subtask 3: 0 / 58