Submission #956728

#	Time	Username	Problem	Language	Result	Execution time	Memory
956728		chrisvilches	Dragon 2 (JOI17_dragon2)	C++14	100 / 100	962 ms	32992 KiB

dragon2

#include <bits/stdc++.h>
using namespace std;

// Score: 60/100
// https://oj.uz/problem/view/JOI17_dragon2

struct Point {
  int x, y, idx, tribe;
  Point operator-(const Point& p) const { return {x - p.x, y - p.y, idx, tribe}; }
  Point operator+(const Point& p) const { return {x + p.x, y + p.y, idx, tribe}; }
  long long cross(const Point& p) const {
    return x * (long long)p.y - y * (long long)p.x;
  }

  Point negate() const { return {-x, -y, idx, tribe}; }
};

// short orientation(const Point& o, const Point& a, const Point& b) {
//   const long long x = (a - o).cross(b - o);
//   return (x > 0) - (x < 0);
// }

Point A, B;
map<pair<int, int>, int> query_ans;

bool above(const Point& p) { return B.cross(p) > 0; }

Point to_upper(const Point& p) { return above(p) ? p : p.negate(); }
bool operator<(const Point& p, const Point& q) {
  return to_upper(p).cross(to_upper(q)) > 0;
}

bool cmp_by_b(const Point& p, const Point& q) {
  const bool a1 = above(p);
  const bool a2 = above(q);
  if (a1 != a2) return a1;
  return p.cross(q) > 0;
}

const int bit_n = 30'001;
short bit[bit_n];

void clear(const int n) { memset(bit, 0, sizeof(short) * n); }

int sum(int r) {
  int ret = 0;
  for (; r >= 0; r = (r & (r + 1)) - 1) ret += bit[r];
  return ret;
}

int sum(int l, int r) { return sum(r) - sum(l - 1); }

void add(int idx, const short delta) {
  for (; idx < bit_n; idx = idx | (idx + 1)) bit[idx] += delta;
}

void query_attacked_by(const vector<Point>& points1, const vector<Point>& points2,
                       const vector<Point>& ord_b, const int tribe_idx) {
  if (points1.empty() || points2.empty()) return;

  clear(points2.size());

  int j = 0;

  for (const Point& p : points1) {
    int total = 0;

    while (j < (int)points2.size()) {
      const Point& q = points2[j];

      if (p < q) break;
      add(q.idx, 1);

      j++;
    }

    const auto mid = lower_bound(ord_b.begin(), ord_b.end(), B.negate(), cmp_by_b);

    if (above(p)) {
      // TODO: "mid" is probably not necessary, since p is always "above",
      //       mid isn't touched, maybe?
      const auto it = lower_bound(ord_b.begin(), mid, p - B, cmp_by_b);
      const int idx = it - ord_b.begin();
      const int all = idx;
      const int enabled = sum(0, idx - 1);
      total += all - enabled;

      const auto it2 = lower_bound(mid, ord_b.end(), B - p, cmp_by_b);

      const int all_below = it2 - mid;
      const int enabled_below = sum(mid - ord_b.begin(), it2 - ord_b.begin() - 1);
      total += all_below - enabled_below;

    } else {
      auto it = lower_bound(ord_b.begin(), ord_b.end(), p - B, cmp_by_b);
      // TODO: What do you want? Is it necessary?
      // if (it != ord_b.end() && cmp_by_b(*it, p - B)) it++;
      if (it != ord_b.end()) {
        total += sum(it - ord_b.begin(), ord_b.size() - 1);
      }

      auto it2 = lower_bound(ord_b.begin(), mid, B - p, cmp_by_b);
      total += sum(it2 - ord_b.begin(), mid - ord_b.begin() - 1);
    }

    query_ans[{tribe_idx, p.tribe}] += total;
  }
}

void query(const vector<Point>& points1, const vector<Point>& points2,
           const vector<Point>& ord_b, const int tribe_idx) {
  if (points1.empty() || points2.empty()) return;

  clear(points2.size());

  int j = 0;

  for (const auto& q : points2) {
    if (!above(q)) add(q.idx, 1);
  }

  for (const Point& p : points1) {
    while (j < (int)points2.size()) {
      const Point& q = points2[j];

      if (p < q) break;
      add(q.idx, above(q) ? 1 : -1);

      j++;
    }

    Point from = p - B;
    Point to = B - p;

    if (!above(p)) swap(from, to);

    const int a = lower_bound(ord_b.begin(), ord_b.end(), from, cmp_by_b) - ord_b.begin();
    const int b = lower_bound(ord_b.begin(), ord_b.end(), to, cmp_by_b) - ord_b.begin();

    query_ans[{p.tribe, tribe_idx}] += sum(a, b - 1);
  }
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int N, M, Q;

  while (cin >> N >> M) {
    vector<vector<Point>> tribe_points(M + 1);
    vector<vector<Point>> order_by_b(M + 1);

    for (int i = 0; i < N; i++) {
      Point p;
      cin >> p.x >> p.y >> p.tribe;
      tribe_points[p.tribe].push_back(p);
    }

    cin >> A.x >> A.y;
    cin >> B.x >> B.y;
    cin >> Q;
    B = B - A;

    for (int m = 0; m <= M; m++) {
      auto& points = tribe_points[m];
      for (auto& p : points) p = p - A;
      for (auto& p : points) p = p - B;
      sort(points.begin(), points.end(), cmp_by_b);
      for (int i = 0; i < (int)points.size(); i++) points[i].idx = i;
      auto& b = order_by_b[m];
      b = points;
      for (auto& p : points) p = p + B;
      sort(points.begin(), points.end());
    }

    map<int, set<int>> attacks;
    map<int, set<int>> attacked;
    map<pair<int, int>, bool> query_done;
    vector<pair<int, int>> query_original_order;
    query_ans.clear();

    while (Q--) {
      int i, j;
      cin >> i >> j;
      attacks[i].emplace(j);
      attacked[j].emplace(i);
      query_original_order.emplace_back(i, j);
      // query(tribe_points[i], tribe_points[j], order_by_b[j], j);
      // query(tribe_points[i], tribe_points[j], order_by_b[j], j);
      // cout << query_ans[{i, j}] << '\n';
    }

    vector<tuple<long long, int, bool>> queries;
    for (const auto& [tribe_idx, other] : attacks) {
      // tribe_idx uses BIT
      const long long bit_weight = tribe_points[tribe_idx].size() * other.size();
      queries.emplace_back(bit_weight, tribe_idx, true);
    }
    for (const auto& [tribe_idx, other] : attacked) {
      // tribe_idx uses BIT
      const long long bit_weight = tribe_points[tribe_idx].size() * other.size();
      queries.emplace_back(bit_weight, tribe_idx, false);
    }

    sort(queries.rbegin(), queries.rend());

    set<pair<int, int>> visited;

    for (const auto& [_, tribe_idx, is_attack] : queries) {
      vector<Point> all;

      if (is_attack) {
        for (const int other_tribe_idx : attacks[tribe_idx]) {
          const pair<int, int> query_pair{tribe_idx, other_tribe_idx};
          if (visited.count(query_pair)) continue;

          for (const Point& p : tribe_points[other_tribe_idx]) all.emplace_back(p);
          visited.emplace(query_pair);
        }
      } else {
        for (const int other_tribe_idx : attacked[tribe_idx]) {
          const pair<int, int> query_pair{other_tribe_idx, tribe_idx};
          if (visited.count(query_pair)) continue;

          for (const Point& p : tribe_points[other_tribe_idx]) all.emplace_back(p);
          visited.emplace(query_pair);
        }
      }

      sort(all.begin(), all.end());

      if (is_attack) {
        query_attacked_by(all, tribe_points[tribe_idx], order_by_b[tribe_idx], tribe_idx);
      } else {
        query(all, tribe_points[tribe_idx], order_by_b[tribe_idx], tribe_idx);
      }
    }

    // cerr << "--" << rand() << endl;
    for (const auto& [i, j] : query_original_order) {
      const int ans = query_ans[{i, j}];
      cout << ans << '\n';
    }
  }
}

Compilation message (stderr)

dragon2.cpp: In function 'int main()':
dragon2.cpp:194:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  194 |     for (const auto& [tribe_idx, other] : attacks) {
      |                      ^
dragon2.cpp:199:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  199 |     for (const auto& [tribe_idx, other] : attacked) {
      |                      ^
dragon2.cpp:209:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  209 |     for (const auto& [_, tribe_idx, is_attack] : queries) {
      |                      ^
dragon2.cpp:240:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  240 |     for (const auto& [i, j] : query_original_order) {
      |                      ^

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40