Submission #172244

#	Time	Username	Problem	Language	Result	Execution time	Memory
172244		golikovnik	Aliens (IOI16_aliens)	C++14	41 / 100	2059 ms	94152 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;
  {
    for (int i = 0; i < n; ++i) {
      if (r[i] < c[i]) {
        swap(r[i], c[i]);
      }
    }
    vector<int> p(n);
    iota(p.begin(), p.end(), 0);
    sort(p.begin(), p.end(), [&](int i, int j) {
      if (r[i] != r[j]) {
        return r[i] < r[j];
      }
      return c[i] > c[j];
    });
    for (int i = 0; i < n; ++i) {
      while (!a.empty() && a.back().c >= c[p[i]]) {
        a.pop_back();
      }
      a.emplace_back(r[p[i]], c[p[i]]);
    }
  }
  auto relax = [&](i64& x, i64 y) {
    if (y < x) {
      x = y;
      return true;
    }
    return false;
  };
  auto sqr = [](i64 x) {
    return x * x;
  };
  n = (int) a.size();
  i64 const INF = (i64) 1e18;
  mx = min(mx, n);
  vector<vector<i64>> dp(n + 1, vector<i64>(mx + 1, INF));
  fill(dp[0].begin(), dp[0].end(), 0);
  vector<vector<int>> opt(n + 1, vector<int>(mx + 1));
  //  opt[i][j] <= opt[i + 1][j] <= opt[i + 1][j + 1]
  for (int i = 0; i < n; ++i) {
    for (int k = mx; k >= 1; --k) {
      for (int j = opt[i][k]; j <= (k == mx ? i : opt[i + 1][k + 1]); ++j) {
        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));
        if (relax(dp[i + 1][k], dp[j][k - 1] + my_area - inter_area)) {
          opt[i + 1][k] = j;
        }
      }
    }
  }
  return dp.back().back();
}

//int main() {
//  vector<int> r{0, 2, 3};
//  vector<int> c{2, 2, 1};
//  int n = (int) r.size();
//  int m = -1;
//  int k = n;
//  cout << take_photos(n, m, k, r, c) << '\n';
//}

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