Submission #305527

#	Time	Username	Problem	Language	Result	Execution time	Memory
305527		rama_pang	Stations (IOI20_stations)	C++14	100 / 100	1065 ms	1448 KiB

stations

#include "stations.h"
#include <bits/stdc++.h>
using namespace std;

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
  vector<int> labels(n);
  vector<vector<int>> adj(n);
  for (int i = 0; i + 1 < n; i++) {
    adj[u[i]].emplace_back(v[i]);
    adj[v[i]].emplace_back(u[i]);
  }
  vector<int> st(n), et(n);
  int timer = 0;
  const function<void(int, int, int)> Dfs = [&](int u, int p, int odd) {
    st[u] = timer++;
    for (auto v : adj[u]) if (v != p) {
      Dfs(v, u, odd ^ 1);
    }
    et[u] = timer++;
    if (odd) {
      labels[u] = st[u];
    } else {
      labels[u] = et[u];
    }
  };
  Dfs(0, -1, 0);
  vector<int> coords = labels;
  sort(begin(coords), end(coords));
  for (int i = 0; i < n; i++) {
    labels[i] = lower_bound(begin(coords), end(coords), labels[i]) - begin(coords);
  }
  return labels;
}

int find_next_station(int s, int t, vector<int> c) {
  if (s < *min_element(begin(c), end(c))) {
    int par = c.back();
    for (auto u : c) {
      if (u != par && s <= t && t <= u) {
        return u;
      }
    }
    return par;
  } else {
    reverse(begin(c), end(c));
    int par = c.back();
    for (auto u : c) {
      if (u != par && u <= t && t <= s) {
        return u;
      }
    }
    return par;
  }
}

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 61 / 61