Submission #1135786

#	Time	Username	Problem	Language	Result	Execution time	Memory
1135786		m_bezrutchka	Regions (IOI09_regions)	C++20	100 / 100	2751 ms	49804 KiB

regions

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

#define int long long

const int MAXN = 2e5 + 10;
const int SQRT = 512;
vector<int> adj[MAXN];
int n, r, q;
int cnt[SQRT];
int tot[SQRT][SQRT], reg[MAXN], sup[MAXN];
int id_large[MAXN];
vector <int> large;
vector<int> pos[MAXN], vals[MAXN], pos2[MAXN];
int tin[MAXN], tout[MAXN], tcur;

void dfs_sub_1(int v) {
  int rid = id_large[reg[v]];
  if (rid) {
    for (int i = 1; i < (int) large.size(); i++) {
      tot[i][rid] += cnt[i];
    }
    cnt[rid]++;
  }
  for (int w: adj[v]) {
    dfs_sub_1(w);
  }
  if (rid) {
    cnt[rid]--;
  }
}

void dfs_sub_2(int v) {
  tin[v] = ++tcur;
  pos[reg[v]].push_back(tin[v]);
  vals[reg[v]].push_back(v);
  for (int w: adj[v]) {
    dfs_sub_2(w);
  }
  tout[v] = tcur;
  pos2[reg[v]].push_back(tout[v]);
}

int query(int l, int r, int x) {
  auto it_l = lower_bound(pos[x].begin(), pos[x].end(), l);
  auto it_r = upper_bound(pos[x].begin(), pos[x].end(), r);
  return it_r - it_l;
}

int query_inv(int i, int x) {
  int it_l = upper_bound(pos[x].begin(), pos[x].end(), i) - pos[x].begin();
  int it_r = lower_bound(pos2[x].begin(), pos2[x].end(), i) - pos2[x].begin();
  return it_l - it_r;
}

void solve() {
  large.push_back(0);
  cin >> n >> r >> q;
  cin >> reg[1];
  for (int i = 2; i <= n; i++) {
    cin >> sup[i] >> reg[i];
    adj[sup[i]].push_back(i);
  }
  dfs_sub_2(1);
  for (int i = 1; i <= r; i++) {
    sort(pos2[i].begin(), pos2[i].end());
  }

  for (int i = 1; i <= r; i++) {
    if ((int) vals[i].size() > 500) {
      id_large[i] = large.size();
      large.push_back(i);
    }
  }
  dfs_sub_1(1);

  while (q--) {
    int x, y;
    cin >> x >> y;
    int resp = 0;
    if (!id_large[x]) {
      for (int v: vals[x]) {
        resp += query(tin[v], tout[v], y);
      } 
    } else if (!id_large[y]) {
      for (int v: vals[y]) {
        resp += query_inv(tin[v], x);
      }
    } else {
      resp = tot[id_large[x]][id_large[y]];
    }
    cout << resp << endl;
  }
}

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  solve();
  return 0;
}

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