Submission #172221

#	Time	Username	Problem	Language	Result	Execution time	Memory
172221		golikovnik	Aliens (IOI16_aliens)	C++14	12 / 100	87 ms	2424 KiB

aliens

#include <bits/stdc++.h>

using namespace std;

using i64 = long long;

i64 take_photos(int n, int, int mx, vector<int> r, vector<int> c) {
  struct cell {
    int r, c;

    cell(int r, int c) : r(r), c(c) {}
  };
  vector<cell> a;
  {
    vector<int> p(n);
    iota(p.begin(), p.end(), 0);
    sort(p.begin(), p.end(), [&](int i, int j) {
      return tie(r[i], c[i]) < tie(r[j], c[j]);
    });
    for (int i = 0; i < n; ++i) {
      if (r[p[i]] < c[p[i]]) {
        swap(r[p[i]], c[p[i]]);
      }
      while (!a.empty() && a.back().c >= c[p[i]]) {
        a.pop_back();
      }
      a.emplace_back(r[p[i]], c[p[i]]);
    }
  }
  n = (int) a.size();
  i64 const INF = (i64) 1e18;
  mx = min(mx, n);
  vector<vector<i64>> dp(n + 1, vector<i64>(mx + 1, INF));
  dp[0][0] = 0;
  auto relax = [&](i64& x, i64 y) {
    if (y < x) {
      x = y;
    }
  };
  auto sqr = [](i64 x) {
    return x * x;
  };
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j <= i; ++j) {
      for (int k = 1; k <= min(mx, i + 1); ++k) {
        auto his_c = a[j].c;
        auto my_area = sqr(a[i].r - his_c + 1);
        auto inter_area = !j ? 0 : sqr(
                max<i64>(0, a[j - 1].r - his_c + 1));
        relax(dp[i + 1][k], dp[j][k - 1] + my_area - inter_area);
      }
    }
  }
  return *min_element(dp.back().begin(), dp.back().end());
}

//int main() {
//  vector<int> r{0, 0};
//  vector<int> c{2, 0};
//  int n = (int) r.size();
//  int m = -1;
//  int k = n;
//  cout << take_photos(n, m, k, r, c) << '\n';
//}

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