Submission #806150

#	Time	Username	Problem	Language	Result	Execution time	Memory
806150		arush_agu	Birthday gift (IZhO18_treearray)	C++17	56 / 100	24 ms	1136 KiB

treearray

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2")
#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#ifdef DEBUG
#include <time.h>
#endif

#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x)                                                                 \
  {                                                                            \
    ++recur_depth;                                                             \
    auto x_ = x;                                                               \
    --recur_depth;                                                             \
    cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":"           \
         << __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl;         \
  }
#else
#define dbg(x)
#endif

using namespace std;
using namespace __gnu_pbds;

typedef pair<int, int> ii;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;

typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;

typedef vector<bool> vb;

template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
                         tree_order_statistics_node_update>;

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
                                    !is_same<T_container, string>::value,
                                    typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
  os << '{';
  string sep;
  for (const T &x : v)
    os << sep << x, sep = ", ";
  return os << '}';
}

const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;

const int MAXN = 2020;
const int MAX_EULER = MAXN * 2 + 10;
const int MAXLG = 22;

int n, m, q;
vi adj[MAXN];
int a[MAXN];
int depth[MAXN];
ii euler_tour[MAXLG][MAX_EULER];
int first_occ[MAXN], lg2[MAX_EULER];
int tin[MAXN], tout[MAXN];

void solve() {
  cin >> n >> m >> q;
  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    adj[u].push_back(v), adj[v].push_back(u);
  }

  for (int i = 0; i < m; i++)
    cin >> a[i], a[i]--;

  int timer = 0;
  int euler_sz = 0;
  function<void(int, int, int)> f = [&](int u, int p, int d) {
    depth[u] = d;
    first_occ[u] = euler_sz;
    euler_tour[0][euler_sz++] = {d, u};
    tin[u] = timer++;

    for (int &v : adj[u])
      if (v != p) {
        f(v, u, d + 1);
        euler_tour[0][euler_sz++] = {d, u};
      }

    tout[u] = timer++;
  };
  f(0, -1, 0);

  lg2[1] = 0;
  for (int i = 2; i < MAX_EULER; i++)
    lg2[i] = lg2[i / 2] + 1;

  for (int j = 1; j < MAXLG; j++)
    for (int i = 0; i + (1 << j) <= euler_sz; i++)
      euler_tour[j][i] =
          min(euler_tour[j - 1][i], euler_tour[j - 1][i + (1 << (j - 1))]);

  auto is_anc = [&](int u, int v) {
    return tin[u] <= tin[v] && tout[v] <= tout[u];
  };

  auto lca = [&](int u, int v) {
    if (u == v)
      return u;
    if (first_occ[u] > first_occ[v])
      swap(u, v);
    int k = lg2[first_occ[v] - first_occ[u] + 1];
    return min(euler_tour[k][first_occ[u]],
               euler_tour[k][first_occ[v] - (1 << k) + 1])
        .second;
  };

  while (q--) {
    int t;
    cin >> t;
    if (t == 1) {
      int p, v;
      cin >> p >> v;
      a[p - 1] = v - 1;
    } else {
      int l, r, v;
      cin >> l >> r >> v;
      l--, r--, v--;

      bool flag = 0;
      int prev = -1;
      int curr = -1;
      for (int i = l; i <= r; i++) {
        if (!is_anc(v, a[i])) {
          curr = prev = -1;
          continue;
        }

        if (curr == -1)
          curr = a[i], prev = i;
        else
          curr = lca(curr, a[i]);

        if (curr == v) {
          flag = 1;
          cout << prev + 1 << " " << i + 1 << "\n";
          break;
        }
      }

      if (!flag)
        cout << "-1 -1\n";
    }
  }
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);

  clock_t start = clock();

  int test_cases = 1;
  // cin >> test_cases;

  while (test_cases--)
    solve();

#ifdef DEBUG
  cerr << fixed << setprecision(10)
       << "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
       << "s\n";
#endif
  return 0;
}

Compilation message (stderr)

treearray.cpp: In function 'int main()':
treearray.cpp:203:11: warning: unused variable 'start' [-Wunused-variable]
  203 |   clock_t start = clock();
      |           ^~~~~

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