Submission #951828

#	Time	Username	Problem	Language	Result	Execution time	Memory
951828		ind1v	Birthday gift (IZhO18_treearray)	C++11	0 / 100	10 ms	45660 KiB

treearray

#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 5;
const int L = 20;

int n, m, q;
vector<int> g[N];
int a[N];
int fst[N], et[2 * N], lv[N];
int lg2[2 * N];
pair<int, int> anc[L][2 * N];
int time_dfs = 0;
set<int> sf[N], pr[N];

void pre_dfs(int u, int p) {
  time_dfs++;
  fst[u] = time_dfs;
  et[time_dfs] = u;
  for (int v : g[u]) {
    if (v != p) {
      lv[v] = lv[u] + 1;
      pre_dfs(v, u);
      time_dfs++;
      et[time_dfs] = u;
    }
  }
}

void build_lca() {
  for (int i = 2; i < 2 * N; i++) {
    lg2[i] = lg2[i >> 1] + 1;
  }
  for (int j = 0; j < L; j++) {
    for (int i = 1; i + (1 << j) - 1 <= time_dfs; i++) {
      anc[j][i] = (j == 0 ? pair<int, int>{lv[et[i]], et[i]} : min(anc[j - 1][i], anc[j - 1][i + (1 << (j - 1))]));
    }
  }
}

int lca(int u, int v) {
  if (fst[u] > fst[v]) {
    swap(u, v);
  }
  int w = lg2[fst[v] - fst[u] + 1];
  return min(anc[w][fst[u]], anc[w][fst[v] - (1 << w) + 1]).second;
}

void upd(int pos, int v) {
  sf[a[pos]].erase(pos);
  if (pos > 1) {
    pr[lca(a[pos - 1], a[pos])].erase(pos - 1);
  }
  if (pos < m) {
    pr[lca(a[pos], a[pos + 1])].erase(pos);
  }
  a[pos] = v;
  sf[a[pos]].insert(pos);
  if (pos > 1) {
    pr[lca(a[pos - 1], a[pos])].erase(pos - 1);
  }
  if (pos < m) {
    pr[lca(a[pos], a[pos + 1])].erase(pos);
  }
}

void solve(int l, int r, int v) {
  auto it = sf[v].lower_bound(l);
  if (it != sf[v].end()) {
    int x = *it;
    if (x <= r) {
      cout << x << ' ' << x << '\n';
      return;
    }
  }
  it = pr[v].lower_bound(l);
  if (it != pr[v].end()) {
    int x = *it;
    if (x <= r - 1) {
      cout << x << ' ' << x + 1 << '\n';
      return;
    }
  }
  cout << -1 << ' ' << -1 << '\n';
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m >> q;
  for (int i = 1; i <= n - 1; i++) {
    int u, v;
    cin >> u >> v;
    g[u].emplace_back(v);
    g[v].emplace_back(u);
  }
  pre_dfs(1, 1);
  build_lca();
  for (int i = 1; i <= m; i++) {
    cin >> a[i];
  }
  for (int i = 1; i <= m; i++) {
    sf[a[i]].insert(i);
    if (i < m) {
      pr[lca(a[i], a[i + 1])].insert(i);
    }
  }
  while (q--) {
    int t;
    cin >> t;
    if (t == 1) {
      int pos, v;
      cin >> pos >> v;
      upd(pos, v);
    } else if (t == 2) {
      int l, r, v;
      cin >> l >> r >> v;
      solve(l, r, v);
    }
  }
  return 0;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 18
• Subtask 3: 0 / 26
• Subtask 4: 0 / 44