Submission #957261

#	Time	Username	Problem	Language	Result	Execution time	Memory
957261		duckindog	Aliens (IOI16_aliens)	C++17	25 / 100	2020 ms	22360 KiB

aliens

#include <bits/stdc++.h>

using namespace std;

#ifndef LOCAL
#include "aliens.h"
#endif



long long take_photos(int n, int m, int k, vector<int> r, vector<int> c) { 
  using pii = pair<int, int>;
  vector<pii> p(n);

  for (int i = 0; i < n; ++i) {
    if (r[i] > c[i]) swap(r[i], c[i]);
    p[i] = {r[i], c[i]};
  }

  auto dis = [&](pii a) { return abs(a.first - a.second) + 1; };
  
  sort(p.begin(), p.end(), [&](const auto& a, const auto& b) { return dis(a) < dis(b); });
  vector<bool> mk(n, true);
  for (int i = 0; i < n; ++i) { 
    if (!mk[i]) continue;
    for (int j = 0; j < i; ++j) if (mk[j] && j != i) { 
      if (p[i].first <= p[j].first && p[j].second <= p[i].second) mk[j] = false;
    }
  }
  int cnt = 0;
  for (int i = 0; i < n; ++i) { 
    cnt += mk[i];
    if (mk[i]) p.push_back(p[i]);
  }
  p.erase(p.begin(), p.begin() + n);
  k = min(k, n = cnt);
  vector<vector<long long>> f(k + 1, vector<long long>(n + 1, 1e15));
  sort(p.begin(), p.end(), [&](const auto& a, const auto& b) { return a.first < b.first; });

  auto cal = [&](int l, int r) { 
    l -= 1; r -= 1;
    long long val = abs(p[l].first - p[r].second) + 1; val *= val;
    if (!l) return val;
    long long pre = max(0, p[l - 1].second - p[l].first + 1); pre *= pre;
    return val - pre;
  };

  f[0][0] = 0;
  for (int i = 1; i <= k; ++i) { 
    for (int j = 1; j <= n; ++j) { 
      auto& ret = f[i][j];
      for (int t = 1; t <= j; ++t) ret = min(ret, f[i - 1][t - 1] + cal(t, j));
    }
  }
  return f[k][n];
}

#ifdef LOCAL
int32_t main() { 
  cin.tie(0)->sync_with_stdio(0);

  int n, m, k; cin >> n >> m >> k;
  vector<int> r(n), c(n);
  for (int i = 0; i < n; ++i) cin >> r[i] >> c[i];

  cout << take_photos(n, m, k, r, c) << "\n";
}
#endif

• Subtask 1: 4 / 4
• Subtask 2: 12 / 12
• Subtask 3: 9 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40