Submission #753756

#	Time	Username	Problem	Language	Result	Execution time	Memory
753756		taher	Regions (IOI09_regions)	C++17	100 / 100	3224 ms	44008 KiB

regions

 #include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "C:\GCC\debug.h"
#else
#define debug(...) void(42)
#endif

const int R = 25005;
map<int, int> done[R];

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, r, q;
  cin >> n >> r >> q;

  vector<vector<int>> at(r);
  vector<vector<int>> adj(n);

  int hRegion;
  cin >> hRegion;
  hRegion--;
  at[hRegion].push_back(0);

  for (int i = 1; i < n; i++) {
    int par, hCurrent;
    cin >> par >> hCurrent;
    --par;
    --hCurrent;
    at[hCurrent].push_back(i);
    adj[par].push_back(i);
  }

  vector<int> euler_tour;
  vector<int> in(n);
  vector<int> out(n);
  function<void(int)> Dfs = [&](int u) {
    in[u] = (int) euler_tour.size();
    euler_tour.push_back(u);

    for (auto v : adj[u]) {
      Dfs(v);
    }

    out[u] = (int) euler_tour.size() - 1;
  };

  Dfs(0);

  vector<vector<int>> all(r);
  vector<vector<array<int, 2>>> inters(r);
  for (int y = 0; y < r; y++) {
    for (auto pt : at[y]) {
      all[y].push_back(in[pt]);
      inters[y].push_back({in[pt], +1});
      inters[y].push_back({out[pt], -1});
    }
    sort(all[y].begin(), all[y].end());
    sort(inters[y].begin(), inters[y].end());
  }

  auto Get = [&](int x, int y) {

    int ptr = 0;
    int cnt = 0;
    int res = 0;
    for (int i = 0; i < (int) all[y].size(); i++) {
      while (ptr < (int) inters[x].size() && inters[x][ptr][0] < all[y][i]) {
        cnt += inters[x][ptr][1];
        ++ptr;
      }
      res += cnt;
    }

    return res;
  };

  for (int i = 0; i < q; i++) {
    array<int, 2> b;
    cin >> b[0] >> b[1];
    --b[0], --b[1];

    if (done[b[0]].count(b[1])) {
      cout << done[b[0]][b[1]] << '\n';
    } else {
      int res = Get(b[0], b[1]);
      done[b[0]][b[1]] = res;
      cout << res << '\n';
    }

    cout.flush();
  }
  return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 85 / 85