Submission #630071

#	Time	Username	Problem	Language	Result	Execution time	Memory
630071		MilosMilutinovic	Meetings 2 (JOI21_meetings2)	C++14	0 / 100	1 ms	320 KiB

meetings2

/**
 *    author:  wxhtzdy
 *    created: 15.08.2022 17:05:33
**/
#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);  
  int n;
  cin >> n;
  vector<vector<int>> g(n);
  for (int i = 0; i < n - 1; i++) {
    int x, y;
    cin >> x >> y;
    --x; --y;
    g[x].push_back(y);
    g[y].push_back(x);
  }
  const int L = 20;
  vector<int> dep(n);
  vector<int> sz(n);
  vector<vector<int>> pr(n, vector<int>(L));
  function<void(int, int)> Dfs = [&](int v, int p) {
    sz[v] = 1;
    pr[v][0] = p;
    for (int u : g[v]) {
      if (u != p) {
        dep[u] = dep[v] + 1;
        Dfs(u, v);
        sz[v] += sz[u];
      }
    }
  };    
  Dfs(0, 0);
  function<int(int, int)> Find = [&](int v, int p) {
    for (int u : g[v]) {
      if (u != p && sz[u] * 2 >= n) {
        return Find(u, v);
      }
    }
    return v;
  };
  int root = Find(0, 0);
  dep[root] = 0;
  for (int j = 1; j < L; j++) {
    for (int i = 0; i < n; i++) {
      pr[i][j] = pr[pr[i][j - 1]][j - 1];
    }
  }
  Dfs(root, root);
  auto LCA = [&](int x, int y) {
    if (dep[x] < dep[y]) {
      swap(x, y);
    }
    for (int i = L - 1; i >= 0; i--) {
      if (dep[pr[x][i]] >= dep[y]) {
        x = pr[x][i];
      }
    }
    if (x == y) {
      return x;
    }
    for (int i = L - 1; i >= 0; i--) {
      if (pr[x][i] != pr[y][i]) {
        x = pr[x][i];
        y = pr[y][i];
      }
    }
    return pr[x][0]; 
  };                   
  auto Dist = [&](int x, int y) {
    return dep[x] + dep[y] - 2 * dep[LCA(x, y)];
  };
  vector<vector<int>> ids(n + 1);
  for (int i = 0; i < n; i++) {
    ids[sz[i]].push_back(i);
  }
  vector<int> ans(n);
  int x = root, y = root, d = 0;
  for (int i = n / 2; i >= 1; i--) {
    for (int z : ids[i]) {
      int dxz = Dist(x, z);
      int dyz = Dist(y, z);
      if (dxz > d) {
        d = dxz;
        y = z;
      } else if (dyz > d) {
        d = dyz;
        x = z;
      }
    }
    ans[i] = d;
  }
  for (int i = 1; i <= n; i++) {
    cout << (i % 2 == 1 ? 1 : ans[i / 2] + 1) << '\n';
  }
  return 0;
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 16
• Subtask 3: 0 / 80