Submission #320270

#	Time	Username	Problem	Language	Result	Execution time	Memory
320270		AlexLuchianov	Teleporters (IOI08_teleporters)	C++14	100 / 100	635 ms	65536 KiB

teleporters

#include <iostream>
#include <vector>
#include <cassert>
#include <cmath>
#include <set>
#include <map>
#include <algorithm>

using ll = long long;
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MAX(a, b) (((a) < (b)) ? (b) : (a))

int const nmax = 1000000;
int edge[5 + 2 * nmax], seen[5 + nmax * 2];

int extract(int node) {
  int start = node;
  int _count = 0;
  std::vector<int> aux;

  do {
    seen[node] = 1;
    _count++;
    node = edge[node];
    aux.push_back(node);
  } while(start != node);
  
  return _count;
}

int main() {
  std::ios::sync_with_stdio(0);
  std::cin.tie(0);

  int n, m;
  std::cin >> n >> m;
  std::vector<std::pair<int,int>> points;
  points.push_back({0, 0});
  points.push_back({nmax * 2 + 1, 1});

  for(int i = 1;i <= n; i++) {
    int start, stop;
    std::cin >> start >> stop;
    points.push_back({start, i * 2});
    points.push_back({stop, i * 2 + 1});
  }
  std::sort(points.begin(), points.end());
  for(int i = 0; i < points.size() - 1; i++) 
    edge[points[i].second] = (points[i + 1].second ^ 1);
  int result = extract(0) - 1;
  std::vector<int> cycles;
  for(int i = 2; i <= 2 * n + 1; i++)
    if(seen[i] == 0)
      cycles.push_back(extract(i));
  std::sort(cycles.begin(), cycles.end());
  std::reverse(cycles.begin(), cycles.end());

  for(int i = 0; i < cycles.size() && 0 < m; i++) {
    result += cycles[i] + 2;
    m--;
  }

  std::cout << result + m * 2 - m % 2;
  return 0;
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:48:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |   for(int i = 0; i < points.size() - 1; i++)
      |                  ~~^~~~~~~~~~~~~~~~~~~
teleporters.cpp:58:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |   for(int i = 0; i < cycles.size() && 0 < m; i++) {
      |                  ~~^~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
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