제출 #670525

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
670525		MilosMilutinovic	Meetings 2 (JOI21_meetings2)	C++14	100 / 100	624 ms	63900 KiB

meetings2

#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 = 1; i < n; i++) {
    int u, v;
    cin >> u >> v;
    --u; --v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  vector<int> sz(n);
  function<void(int, int)> DfsSz = [&](int v, int pv) {
    sz[v] = 1;
    for (int u : g[v]) {
      if (u == pv) {
        continue;
      }
      DfsSz(u, v);
      sz[v] += sz[u];
    }
  };
  DfsSz(0, 0);
  function<int(int, int)> Find = [&](int v, int pv) {
    for (int u : g[v]) {
      if (u == pv) {
        continue;
      }
      if (sz[u] * 2 >= n) {
        return Find(u, v);
      }
    }
    return v;
  };
  int c = Find(0, 0);
  const int L = 25;
  vector<vector<int>> jump(n, vector<int>(L));
  vector<int> dep(n);
  vector<int> dfn(n);
  vector<int> dfo(n);
  int T = 0;
  function<void(int, int)> Dfs = [&](int v, int pv) {
    dfn[v] = ++T;
    sz[v] = 1;
    jump[v][0] = pv;
    for (int u : g[v]) {
      if (u == pv) {
        continue;
      }
      dep[u] = dep[v] + 1;
      Dfs(u, v);
      sz[v] += sz[u];
    }
    dfo[v] = T;
  };
  Dfs(c, c);
  for (int j = 1; j < L; j++) {
    for (int i = 0; i < n; i++) {
      jump[i][j] = jump[jump[i][j - 1]][j - 1];
    }
  }
  auto LCA = [&](int x, int y) {
    if (dep[x] < dep[y]) {
      swap(x, y);
    }
    for (int i = L - 1; i >= 0; i--) {
      if (dep[jump[x][i]] >= dep[y]) {
        x = jump[x][i];
      }
    }
    if (x == y) {
      return x;
    }
    for (int i = L - 1; i >= 0; i--) {
      if (jump[x][i] != jump[y][i]) {
        x = jump[x][i];
        y = jump[y][i];
      }
    }
    return jump[x][0];
  };
  auto GetDist = [&](int x, int y) {
    return dep[x] + dep[y] - 2 * dep[LCA(x, y)];
  };
  vector<vector<int>> ver(n + 1);
  for (int i = 0; i < n; i++) {
    ver[sz[i]].push_back(i);
  }
  int x = c;
  int y = c;
  int d = 0;
  vector<int> ans(n + 1);
  for (int i = n / 2; i >= 1; i--) {
    for (int z : ver[i]) {
      int d_xz = GetDist(x, z);
      int d_yz = GetDist(y, z);
      if (d_xz < d_yz) {
        swap(x, y);
        swap(d_xz, d_yz);
      }
      if (d_xz > d) {
        d = d_xz;
        y = z;
      }
    }
    ans[2 * i] = d;
  }
  for (int i = 1; i <= n; i++) {
    cout << ans[i] + 1 << '\n';
  }
  return 0;
}

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