Submission #757818

#	Time	Username	Problem	Language	Result	Execution time	Memory
757818		taher	Untitled (POI11_ins)	C++17	100 / 100	1440 ms	131072 KiB

Main

#include <bits/stdc++.h>
 
using namespace std;
 
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  if (n == 1) {
    cout << 0 << '\n';
    return 0;
  }
  vector<vector<int>> adj(n);
  for (int i = 0; i < n - 1; i += 1) {
    int a, b;
    cin >> a >> b;
    a -= 1, b -= 1;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  vector<pair<int, int>> dp(n);
  function<pair<int, int>(int, int)> Dfs = [&](int node, int pre) {
    int ans = 1;
    for (auto x : adj[node]) {
      if (x == pre) continue;
      ans += Dfs(x, node).first;
    }
    return dp[node] = make_pair(ans, pre);
  };
  Dfs(0, -1);
  long long ans = 0;
  int max_depth = 0;
  function<void(int, int, int, int, bool)> Get = [&](int node, int pre, int depth, int sub, bool now) {
    if (now) {
      max_depth = max(depth, max_depth);
    }
    ans += 1LL * depth * 2;
    for (auto x : adj[node]) {
      if (x == pre) continue;
      bool c1 = (x == sub || sub == -1);
      Get(x, node, depth + 1, sub, now | c1);
    }
    return;
  };
  auto Init = [&]() {
    max_depth = 0;
    ans = 0;
    return;
  };
  vector<int> sum(n);
  for (int i = 0; i < n; i++) {
    for (auto x : adj[i]) {
      if (x == dp[i].second) continue;
      sum[i] += dp[x].first;
    }
  }
  for (int node = 0; node < n; node += 1) {
    vector<pair<int, int>> comps;
    int id = 0, cnt = 0;
    for (auto x : adj[node]) {
      int sz = (x == dp[node].second ? n - 1 - sum[node] : dp[x].first);
      comps.emplace_back(sz, x);
      if (comps[id].first <= sz) {
        id = cnt;
      }
      cnt += 1;
    }
    int mx = comps[id].first;
    int sub = comps[id].second;
    if (mx > n - mx) {
      cout << -1 << '\n';
      continue;     
    }
    else {
      if (n - 2 * mx == 0) {
        Get(node, -1, 0, sub, 0);        
      }
      else {
        Get(node, -1, 0, -1, 0);
      }
      cout << ans - max_depth << '\n';
      Init();
    }
  }
  return 0; 
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10