제출 #415220

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
415220		Alex_tz307	Regions (IOI09_regions)	C++17	80 / 100	8079 ms	37804 KiB

regions

#include <bits/stdc++.h>

using namespace std;

const int MAXN = 2e5;
const int MAXR = 25 * 1e3;
const int BLOCK = 445;
int m, r[MAXN], timer, in[MAXN], out[MAXN], cnt_large, ind[MAXR], dp[MAXR], child[BLOCK][MAXR];
vector<int> G[MAXN], R[MAXR], pos[MAXR];

void dfs1(int u) {
  in[u] = ++timer;
  pos[r[u]].emplace_back(in[u]);
  for (int v : G[u])
    dfs1(v);
  out[u] = timer;
}

void dfs2(int u, int region) {
  if (r[u] == region)
    for (int i = 0; i < m; ++i)
      child[ind[region]][i] += dp[i];
  ++dp[r[u]];
  for (int v : G[u])
    dfs2(v, region);
  --dp[r[u]];
}

int solve(int r1, int r2) {
  int ans = 0;
  for (int u : R[r1]) {
    int n = pos[r2].size();
    int st = n, dr = n, l = 0, r = n - 1;
    while (l <= r) {
      int mid = (l + r) >> 1;
      if (in[u] <= pos[r2][mid]) {
        st = mid;
        r = mid - 1;
      } else l = mid + 1;
    }
    l = 0, r = n - 1;
    while (l <= r) {
      int mid = (l + r) >> 1;
      if (out[u] < pos[r2][mid]) {
        dr = mid;
        r = mid - 1;
      } else l = mid + 1;
    }
    ans += dr - st;
  }
  return ans;
}

int main() {
  int n, Q;
  cin >> n >> m >> Q;
  for (int v = 0; v < n; ++v) {
    if (v == 0) {
      cin >> r[0];
      --r[0];
      R[r[0]].emplace_back(0);
      continue;
    }
    int u;
    cin >> u >> r[v];
    --r[v];
    G[u - 1].emplace_back(v);
    R[r[v]].emplace_back(v);
  }
  dfs1(0);
  for (int i = 0; i < m; ++i)
    if ((int)R[i].size() > BLOCK){
      ind[i] = cnt_large++;
      for (int j = 0; j < m; ++j)
        dp[j] = 0;
      dfs2(0, i);
    }
  map<pair<int,int>,int> sol;
  for (int q = 0; q < Q; ++q) {
    int r1, r2;
    cin >> r1 >> r2;
    --r1, --r2;
    if ((int)R[r2].size() > BLOCK) {
      cout << child[ind[r2]][r1] << '\n';
      cout.flush();
      continue;
    }
    pair<int,int> p{r1, r2};
    auto it = sol.find(p);
    if (it != sol.end())
      cout << it->second << '\n';
    else {
      int ans = solve(r1, r2);
      sol[p] = ans;
      cout << ans << '\n';
    }
    cout.flush();
  }
  return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 65 / 85