Submission #1029577

#TimeUsernameProblemLanguageResultExecution timeMemory
1029577kunzaZa183Teleporters (IOI08_teleporters)C++17
80 / 100
340 ms65536 KiB
#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  int n, m;
  cin >> n >> m;
  unordered_map<int,int> tp;
  vector<pair<int, int>> vpii;
  {
    vector<int> vi;
    for (int i = 0; i < n; i++) {
      int a, b;
      cin >> a >> b;
      vi.push_back(a), vi.push_back(b);
      tp[a] = b, tp[b] = a;
    }
    sort(vi.begin(), vi.end());
    vpii.emplace_back(0, vi[0]);
    for (int i = 0; i < vi.size() - 1; i++) {
      vpii.emplace_back(vi[i], vi[i + 1]);
    }
    vpii.emplace_back(vi.back(), 3e6);
  }
  // for (auto a : vpii) cout << a.first << " " << a.second << "\n";
  vector<bool> vb;
  vb.resize(vpii.size());
  vector<int> cyc;
  int special;
  for (int i = 0; i < vb.size(); i++)
    if (!vb[i]) {
      // cout << "I = " << i << '\n';
      int cy = 0;
      function<void(int)> dfs;
      dfs = [&](int cur) {
        // cout << cur << "\n";
        if (vb[cur]) {
          cyc.push_back(cy);
          return;
        }
        vb[cur] = 1;
        cy++;
        if (vpii[cur].second == 3e6) {
          special = cy - 1;
          return;
        }
        dfs(lower_bound(vpii.begin(), vpii.end(),
                        make_pair(tp[vpii[cur].second], -1)) -
            vpii.begin());
      };
      dfs(i);
    }
  // for (auto a : cyc) cout << a << ' ';
  // cout << "\n";
  sort(cyc.begin(), cyc.end(), greater<int>());
  if (m >= cyc.size()) {
    int x = (m - cyc.size());
    int val = x / 2 * 4 + x % 2;
    cout << special + accumulate(cyc.begin(), cyc.end(), 0) + cyc.size() * 2 + val
         << "\n";
  } else
    cout << special + accumulate(cyc.begin(), cyc.begin() + m, 0) + 2 * m
         << "\n";
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:20:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |     for (int i = 0; i < vi.size() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~
teleporters.cpp:30:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<bool>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |   for (int i = 0; i < vb.size(); i++)
      |                   ~~^~~~~~~~~~~
teleporters.cpp:56:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   if (m >= cyc.size()) {
      |       ~~^~~~~~~~~~~~~
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